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IntroductionIn the world of electrical safety and circuit protection, PCT resettable fuses have gained attention as the primary support for a complete set of safety features that protect electronic devices from the damages caused by overcurrent and short circuit conditions. Innovative self-repairing devices that caused a stir in the market and became the trend in consumer electronics and auto driving are among the examples of such applications. This guide covers PTC resettable fuses from A to Z, explaining their derivate purpose, capabilities, areas of application, and physical characteristics, aiding with knowledge on the subject by professionals and hobbyists. Positive Temperature Coefficient (PTC) Resettable FusesThe Positive Temperature Coefficient (PTC) fuse is a resettable fuse for overcurrent fault protection that instantly resets after a fault condition occurs and is cleared. In contrast to a standard fuse that will be discarded after being used to break a circuit, the PTC fuse is in the normal state and can be used again. The electric fuse unites this specific property into its unique performance principle. This PTC thermistor means that the more heat the fuse is exposed to, the higher its resistance, and so does the capacity of the current flow limit in the case of an overcurrent. Types of Resettable FusesThere are two main types of resettable fuses: such as radial and surface mount leads. Each type has its unique characteristics and applications:Radial Leaded: These PTC parts are recommended for a hole drilled through which they are installed on a printed circuit board (PCB). They are found in the power supplies, chargers, and a lot of electronics products.Surface Mount: Surface mount resettable fuses are built for automatic assembly on the printed circuit board (PCB) through surface mount technology (SMT). They are small in size and can provide maximum current condition. The surface mount PTC units are commonly seen in high-density electronic applications, like smartphones and tablets. How Positive Temperature Coefficient (PTC) Resettable Fuses WorkThe core operation principle of a PTC fuse is based on the PTC thermistor material, consisting of a polymer or ceramic blend. In a normal state of operation, the fuse is characterized by low resistance in a way that will not interrupt the passing of current through the circuit. However, in case of an overcurrent or short circuit, the thermistor's resistance suddenly increases due to the generated heat. This rise of the resistance is sufficient to reduce the currents to safe levels so that this activity will not harm circuitry devices. Undoing the fault, the machine gets a hold, and thus, the resistance falls back to a level position, most probably allowing the normal flow of current to pass. What are the Specifications of a Resettable Fuse? Holding Current:the most amount of electricity flow the non-resettable fuse can handle and operating modes – from a low resistance state (during regular operation) to a high resistance state (after the maximum current has caused it to trip). The purpose of a fuse is that it holds a current higher than the maximum amount of electricity in a circuit, so it doesn’t trip during regular operation. Trip Current:the level of fullness that the fuse will burst, and then the circuit will be closed. They have high instantaneous currents that engage magnetic circuits, which jump in response to overcurrent conditions. The flow of the trip is usually more significant than the retentive force provided by the contact wires. Rated Voltage:the specified highest surgeable rating that a given fuse can tolerate before breakdown. The fuse voltage rating and the voltage being used must be the same, or the circuit voltage must be lower than the fuse voltage rating. Maximum Current:the maximum amount of electricity that will pass through a fuse, which limits the current to a certain level to avoid hazards. The rated maximum current is usually specified by thermistor manufacturers, taking into consideration the size, composition, and design of the thermistor developed. Max Time to Trip (MTT):the longest possible time it takes between the minimum and maximum of fast transition (a rapid switch from low-resistance state to high-resistance state) when an abnormal current appears. The trip time of the PPTC unit is defined as the duration from the initiation of a fault current till the device gets tripped. It depends on the degree and duration (details) of the fault current flowing and also on ambient temperature. Typical Power:the average amount of power usually could have been produced by a fuse when it tripped in steady air condition with an ambient temperature of 23°C. Advantages of Using Temperature Coefficient (PTC) Resettable FusesThe self-recovering feature of PTC fuses offers multiple advantages: Cost Efficiency:No more replacing the so-called equipment after a fault, less maintenance work will be done, and the times of downtime will be lessened as well. Enhanced Safety:Incorporates insulation reliable in noble protection of overcurrents and short circuits, enhancing electronic safety. Design Flexibility:PTC fuses are highly adjustable with multiple sizes and ratings, and this PTC fuse type can accommodate many applications. Ease of Use:It saves components in the design of the protective circuit as less number of components are required for overcurrent protection. Applications of Right Temperature Coefficient (PTC) Resettable FusePTC resettable fuses are versatile and find applications in multiple fields: Consumer Electronics:Used for current control in charging smartphones, laptops, and battery packs to avoid overcharging or circuit damage. Automotive Electronics:This feature prevents electrical overloads in the vehicle's electronic systems, including audio, lighting, and control units. Telecommunications:Ensure that the communication devices and infrastructure are functional by preventing the overcurrent assisting the damage. Industrial Automation:Prevents electrical faults from damaging industrial equipment and control systems and improves operational performance. Selecting the Right Temperature Coefficient (PTC) Resettable FuseChoosing the appropriate PTC fuse involves considering several factors: Rated Current: Current flowing through the device that the device is able to withstand before it becomes unstable. Therefore, it must be equal to or higher than the nominal working current of the circuit.Trip Current:The operating current that governs the transition of the device from a low-resistance state to a high-resistance state is the critical factor for the operation. It should be higher than the maximum average operating current but lower than the maximum working standard, which would be tiresome on the appliance.Voltage Rating:The maximum working voltage of the device should be given. Make sure you choose a resistor that offers the same or even higher DC voltage than your circuit's operating voltage.Time to Trip:The time the device takes to terminate the overcurrent condition. The time taken for this process of the device is called the time of limitation. It should be compliant and pass safety standards.Form Factor: Regarding the actual size and shape of the fuse, it would be required to verify if they would correspond with the boundaries of the demanded application. Installation and MaintenanceWhile PTC resettable fuses were built to assure longevity and reliability, proper installations should be deemed necessary to ensure they perform better. The installation algorithm should be used in compliance with the given supplier guidelines, including sun orientation and air gaps, to avoid overheating. Regular analysis of the elements can help anticipate the possible ones before they cause the circuits to fail up to date with the protection of your electronic system. ConclusionResettable PTC fuses are a considerable step forward in circuit protection technology. It is indeed a combination of safety, reliability, and cost-effectiveness. Besides providing continuous protection of the grid, their auto-healing nature lessens both maintenance workload and cost thrust. Knowing how to use them, their advantages, and selection criteria, designers and engineers can integrate these devices among a variety of applications, from consumer electronics to automotive systems, and increase the safety and reliability of electronic gadgets.

Introduction Power electronics are pivotal in efficiently converting, controlling, and conserving electric power across residential, commercial, and industrial applications. Employing solid-state electronics helps adjust motor speeds, maintain uninterrupted power flow, enable high-frequency power supplies, integrate renewable energy, and positively impact energy usage from electric vehicles to data centers and spacecraft systems to high-speed rail; power electronics touch every arena. At the epicenter of this technology are semiconductor-switching devices like diodes, MOSFETs, IGBTs, and thyristors that shape and regulate power flow. Two stalwarts dominate for medium to high power needs - the metal-oxide-semiconductor field effect transistor (MOSFET) and the insulated gate bipolar transistor (IGBT). Selecting a suitable device is crucial to optimize overall system performance. This article provides a comparative analysis of these two technologies to help design engineers make an informed choice. Understanding Power MOSFETsPower MOSFETs are specialized transistors designed to switch on/off rapidly, allowing precise and speedy power transfer control. They can transition between cut-off and saturation modes in nanoseconds. This swift switching capability stems from their unique insulated gate structure, requiring minimal gate current to trigger state changes. Built-in body diodes facilitate the continuous conduction of load currents in either direction. Silicon has traditionally been the mainstream material, but new comprehensive bandgap materials like silicon carbide and gallium nitride promise significantly higher efficiency. With high breakdown strength, lower losses, and higher junction temperature capacity, these advanced materials drive a significant shift in power electronics. Exploring IGBT DevicesInsulated gate bipolar transistors (IGBTs) aim to combine the best attributes of power MOSFETs and bipolar junction transistors. They integrate the simple gate control of MOSFETs with the superior high current handling capacity of BJTs. A key feature enabling high collector current density is conductivity modulation, where electron and hole injection sustains current flow. However, this also slows down switching transients. The insulating layer blocks high voltages but leads to larger chip sizes. Modern IGBTs lower losses through innovations like trench gates, carrier lifetime control, and field stop layers. Advanced packaging technologies also boost power density and thermal performance. But slower switching speeds and conduction losses at low currents remain innate drawbacks. Comparing Key Application DomainsMOSFETs' ultrafast and controllable switching ability makes them perfect for switch mode power supplies (SMPS), Class D audio amplifiers, DC-DC converters, and lighting controls needing precise regulation. These applications demand fast dynamic response and low losses at moderate voltage and current levels.IGBTs, on the other hand, are extensively used in motor drives, uninterruptible power supplies (UPS), electric traction systems, wind turbines, HVDC transmission, and high power factor correction equipment. These applications require ruggedness to withstand network voltage fluctuations, high DC link voltages, and surge currents during motor commutation or load changes. IGBTs can reliably handle hundreds to thousands of amperes thanks to conductivity modulation but at the expense of switching speed. Analyzing Switching CharacteristicsMOSFETs can transition between on and off states extremely fast, within nanoseconds. This enables them to comfortably operate at frequencies in the MHz range for switch mode operations. However, their switching speeds are limited by charging and discharging intrinsic capacitances across drain, source, and gate terminals during the high di/dt and dv/dt transients.In contrast, IGBTs switch on and off much slower - in the range of microseconds to milliseconds, depending on load conditions. Their switching times are dictated by minority carrier injection and storage dynamics during turn-on and turn-off, respectively. The conductivity modulation mechanism in IGBTs that enables efficient high current operation also adds more delay during transients. Cost, complexity, and application-specific demands impact device selection, too. Analyzing Conduction LossesMOSFETs offer shallow conduction losses at nominal currents, enabling high efficiency. This stems from majority carrier transport through the drain-to-source channel unimpeded by minority charge storage effects. However, the drift component of on-state resistance limits efficiency at high currents due to velocity saturation.In contrast, IGBTs showcase deteriorating conduction losses at low currents but start outperforming MOSFETs above a few amperes current. This reversal occurs due to conductivity modulation wherein electron and hole injections sustain rising collector current density. IGBTs skip past velocity limits at high currents to achieve significantly higher efficiency. Rating on Voltage and Current MetricsLatest generation SiC MOSFETs boast blocking capabilities exceeding 1.7 kV, while GaN variants enable 1.2 kV switch-mode supplies. Commercial IGBT voltage ratings range from 1.2 kV to 1.7 kV presently. However, IGBT packages reliably exceed 1000 A without secondary breakdown concerns for conducting hundreds of amperes. MOSFETs lag on current density metrics presently. Sensitivity to High-TemperaturesIGBT performance depends significantly on temperature swings and self-heating, needing careful thermal management. MOSFETs show lower sensitivity thanks to the absence of conductivity modulation effects. But hotspots can still accelerate aging and degrade long-term MOSFET reliability over time. Cost Considerations Thanks to process maturity, MOSFET design and production costs have been considerably reduced, making them economical for low- and medium-power applications. However, large-area silicon IGBTs can be fabricated at lower costs to score over MOSFETs in high-voltage, high-current areas. Emerging devices like SiC MOSFETs and GaN transistors promise tremendous performance gains but remain expensive. Gazing into the FutureWith continual advances in device structure, doping profiles, and material quality, MOSFET and IGBT technologies are poised to realize higher efficiency, power density, and reliability metrics. Novel cooling techniques leveraging direct liquid immersion or integrated microchannel heat sinks are being explored to dissipate heat from smaller footprints. Clever gate driver techniques and modern packaging methods will help extract the full potential from both devices. Another active area is developing hybrid modules that combine IGBTs and SiC MOSFETs to leverage their complementary strengths for optimal overall performance. The future looks brighter with the increasing maturity of wide bandgap devices and greater systems-level integration! Making the Optimal ChoiceMOSFETs excel for applications demanding nimble and accurate load control, typically up to a few kilowatts. IGBTs are the bedrock where large voltage blocks and high surge current capacity warrant extra ruggedness. However, cost budget, cooling challenges, reliability requirements, and desired switching frequencies also guide decision-making. Designers must weigh tradeoffs between conduction losses, switching frequencies, thermal management complexity, and hardware overheads while selecting the optimal power semiconductor switch. Conclusion In the vast power electronics landscape, MOSFETs and IGBTs remain the primary switching devices for most applications. MOSFETs stand out in environments needing nimble and accurate switching control up to a few kilowatts. IGBTs are the bedrock for systems where large voltages and surge currents demand extra ruggedness. Device selection requires carefully weighing metrics like losses, operating frequency, cooling needs, and costs. With continual technological upgrades, these devices will continue transforming future power management solutions.

Integrated circuits (ICs) are the fundamental components of modern electronics. They are vital in manufacturing various systems and gadgets, including computers, smartphones, industrial machinery, and medical equipment. Indeed, integrated circuits are electronic components with small sizes and are composed of several parts and functions on a single semiconductor substrate, like silicon.Integrated circuits have various forms, each designed to meet particular needs and applications. Over time, these integrated circuits have developed into increasingly complex, powerful, and adaptable devices. Integrated circuits can be categorized according to several factors, such as their fabrication technology, functionality, and complexity. This article will explain the integrated circuit, its significant types, and the development trends of integrated circuits. What is an Integrated Circuit？An integrated circuit is just like a semiconductor wafer that has thousands or millions of small resistors, capacitors, transistors, and diodes. There are multiple examples of integrated circuits, which are computer memory, counter, oscillator, computer memory, logic gate, timer, processor, and microcontroller. An IC has become the fundamental building element for all modern electric devices. It is an integrated system that contains several miniaturized and interconnected components embedded in a thin silicon chip. An integrated circuit is developed by connecting a vast number of tiny MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) that are crammed onto a tiny chip. Compared to discrete circuits constructed with discrete electronic components, this results in circuits that are substantially faster, smaller, and less expensive.Since ICs can be produced in large quantities and use building blocks for integrated circuit design, the electronics industry has rushed to incorporate standardized ICs into designs that use discrete transistors. ICs are superior to discrete circuits in two crucial ways: cost and performance.Performance is much higher in ICs than in discrete counterparts because the components inside an IC have quicker switch times and use less power due to their proximity and compact size. ICs are highly inexpensive because they are generated by photolithography as a single unit instead of one transistor at a time. Less material is used when you compare packaged circuits to discrete circuits.Integrated circuits constantly evolve due to technological advancements, providing better functionality, lower power consumption, and higher performance. To fully utilize these potent components in their applications, engineers, designers, and enthusiasts must have a thorough understanding of the various types of integrated circuits.However, a significant drawback of integrated circuits is their high design cost and photolithography mask creation. Because of this, ICs can only be profitable when large manufacturing volumes are anticipated, enabling profit margins to justify them.Introduction to All Types of Integrated CircuitsThere are several types of integrated circuits (ICs), each designed especially for a specific use or application. ICs are categorized according to several factors, such as their fabrication technology, functionality, and complexity. Understanding the different types of integrated circuits is essential for engineers, designers, and enthusiasts, as it allows them to select the right ICs for their applications. This guide will discuss the multiple types of integrated circuits.Continuous electrical signals are intended to operate with analog integrated circuits. They are crucial in processing and manipulating analog data from the real world, including sensor signals, audio, and video. These chips can convert analog signals to digital, filtering and amplifying. Analog-to-digital converters (ADCs), voltage regulators, and operational amplifiers (op-amps) are examples of analog integrated circuits.Unlike analog ICs, digital ICs handle discrete digital signals and usually operate at two logic levels: 0 and 1. They are the fundamental digital electronics components of data processing, memory storage, and logical operations. Digital integrated circuits (ICs) include microcontrollers, microprocessors, and memory chips like RAM and flash memory.These circuits serve as a link between the analog and digital realms, combining analog and digital components. They play a role in applications that require processing and interfacing with both types of signals. You can commonly find mixed-signal ICs in telecommunications, audio processing, and sensor interfaces, as they enable converting real-world analog data into form and vice versa.RFICs are designed for high-frequency operations, making them ideal for communication devices such as cell phones, Wi-Fi routers, and satellite communication systems. These ICs excel at handling signals at radio frequencies to transmit and receive information effectively.Microprocessor CircuitsThe most complex integrated circuits are microprocessors. They contain billions of transistors that can be arranged to form countless distinct virtual circuits. Furthermore, every circuit possesses a distinct set of sound judgment qualities. These synchronized circuits, for good judgment, comprise the entirety of a microprocessor. The central processing unit (CPU) of a computer is frequently a microprocessor.             Similar to a marching band, the circuits use the bandmaster's guidance to execute their good judgment on the course best. The bandmaster is enclosed in a microchip and tries to communicate. It refers to the clock as well. The clock represents the ability to move quickly between states of sound judgment. Every time the clock changes states, each of the microprocessor's good judgment circuits does a certain task. Relying on the speed of the microprocessor allows calculations to be completed quickly.Data is stored in a few circuits called registers, which comprise a microprocessor. Every processor features a multitude of distinct register styles. Preprogrammed commands are kept in permanent registers. The output of operations on integers is saved in temporary registers.Digital Sign ProcessorsAn analog waveform that can be electrically recorded in any situation is a sign. An analog waveform quickly altered into a binary integer sequence is called a virtual sign. A virtual sign processor (DSP) processes indicators digitally as streams of 1s and 0s, as the name suggests. An analog-to-virtual converter also called an A-to-D or A/D converter, can convert a speech recording into virtual 1s and 0s.Following that, the virtual voice can be altered through complex mathematical calculations and a DSP. The circuit's DSP rules can be configured to digitally eliminate background noise from the waveform and identify the spaces between spoken words as history noise.Lastly, a D/A converter can transform the processed signal back into an analog signal for listening. Digital processing can filter history noise so fast that there is no discernible delay, and the sign appears to be heard in "real time."Memory CircuitsGenerally speaking, microprocessors should be able to store more statistics than some registers can hold. Massive memory circuits receive this excess of records. Dense arrays of parallel circuits that use voltage states to store records make up memory. The microprocessor's temporary library of programs or instructions is also kept in memory.To provide functionality without requiring additional space, manufacturers always try to reduce the size of memory circuits. Moreover, smaller additives are usually less expensive to produce, operate more effectively, and require less electricity.Application-specific Integrated CircuitsAn analog or digital application-specific integrated circuit (ASIC) performs only one task and cannot be reconfigured. For instance, an RC car's speed controller integrated circuit is hardwired to perform a single function and is never intended to evolve into a microprocessor. An application-specific integrated circuit is not capable of responding to alternative commands.Efficiency plays a role in electronic devices. Power management integrated circuits (ICs) are responsible for controlling and distributing power in systems, ensuring power usage and stable voltage supply. These ICs are commonly found in battery-powered devices like smartphones and laptops, power supplies, and voltage regulation circuits.A virtual circuit accepts the best voltages of specific values. A binary circuit employs optimal states. In this circuit configuration, the binary numbers "on" and "off" represent 1 and 0, respectively. It also makes use of the good judgment of Boolean algebra. (Boolean algebra is also used to perform binary quantity device arithmetic.) These fundamental elements work with the IC layout to enable virtual computer systems and gadgets to perform the desired operations.Development Trends of Integrated CircuitsLet's discuss the emerging trends of Integrated circuits in detail.High IntegrationWith the trend of thin and short electronic devices, consumers now expect products to be lighter, smaller, and packed with features. Manufacturers of consumer electronics have raised the bar for portable mobile devices' power management systems to serve consumers' needs better. Combining several features into a single power management chip can reduce the number of external devices, enhance the system's long-term reliability, decrease solution size, and boost profit margin.High Efficiency and Low Power ConsumptionAs the consumer electronics industry continues to grow, customers are now demanding the best products that have performance and longer battery life. That is why manufacturers maintain low power consumption by improving continuous device performance. Indeed, low-power and high-performance power management chip products are anticipated to be preferred by the market. Low-power power supply design is also becoming a critical technology impacting electronic system design.AI and Machine Learning HardwareSpecialized integrated circuits (ICs) are generated specifically for machine learning and artificial intelligence (AI). Hardware specifically made to speed up AI workloads includes tensor processing units (TPUs) and graphics processing units (GPUs). The development of image recognition, natural language processing, autonomous vehicles, and many other AI-driven technologies depends on these AI-focused integrated circuits. There will likely be an increase in demand for specialized hardware as AI spreads in various industries.More and more integrated circuits (ICs) are programmable and customizable, allowing hardware designers to customize components for particular uses. For example, field-programmable gate arrays (FPGAs) have various applications since they enable logic gate reconfiguration after manufacturing. Another example of a customized integrated circuit (IC) that balances performance and power efficiency is the application-specific integrated circuit (ASIC). These programmability and customization trends allow engineers to tailor their designs to meet specific requirements.Development trends in integrated circuits align with sustainability objectives as people's awareness of how electronics affect the environment grows. This entails using fewer dangerous materials, increasing energy economy, and designing integrated circuits (ICs) for recycling and appropriate disposal. In short, optimizing the end-of-life disposal process for electronic components is becoming a priority, and green IC design practices, like using lead-free and RoHS-compliant materials, have become common.Packaging technologies have advanced to meet the demands for smaller form factors, better thermal management, and enhanced signal integrity as integrated circuits (ICs) become more complex and functional. Indeed, chiplet-based architectures, wafer-level packaging, and three-dimensional stacking are advanced packaging options that give IC designers new ways to tackle the increasing complexity of contemporary electronic systems. Therefore, by minimizing the distances between chip components, these packaging techniques improve performance and reduce energy consumption.The need for reliable and secure ICs is more significant than ever as technology increasingly integrates into our daily lives. Hardware security features such as tamper resistance, secure boot processes, and hardware-based encryption are all included in this trend. Furthermore, supply chain security—ensuring that integrated circuits (ICs) are not compromised during their manufacturing and distribution processes—is becoming increasingly important. This is especially crucial in defense applications and critical infrastructure.ConclusionIn summary, integrated circuits (ICs) are the building blocks of modern electronics, driving innovation and establishing a world of ever-expanding digital technology. We've talked about different types of integrated circuits that can be extremely important in the digital world. These integrated circuits have developed over time, becoming more effective and energy-efficient while also adjusting to the particular requirements of various technologies.Furthermore, integrated circuit development trends are constantly changing to satisfy the ever-increasing demands of the digital era. ICs continue to be at the forefront of technological advancement, whether it is through their pursuit of energy efficiency, security, or specialized hardware for emerging technologies. To effectively navigate the complex landscape of integrated circuit design and production, industry leaders need to stay up to date on these trends.

Introduction IGBT and MOSFET are fully controlled devices and are voltage-driven, that is, the device is turned on or off by controlling the gate voltage. In fact, the structure of the IGBT is an NPN-type MOSFET plus a P-junction, that is, an NPNP structure, which is a P-type BJT driven by MOS in principle. So what is the difference between them? What is the specific connection of them? MOSFET BJT or IGBT - Brief Comparison Catalog Introduction Ⅰ MOSFET & IGBT Review Ⅱ Si IGBT vs SiC MOSFET Ⅲ Different Requirements for Si IGBT and SiC MOSFET 3.1 ON & OFF State 3.2 Short-Circuit Protection 3.3 Interference and Delay Ⅳ IGBT Working Principle by Analogy with MOSFET Ⅴ FAQ Ⅰ MOSFET & IGBT Review MOSFET is a metal-oxide-semiconductor field effect transistor, or metal-insulator-semiconductor. The source and drain of it can be swapped, and they are both N-type regions formed in the P-type backgate. In most cases, these two regions are the same, even if the two ends are reversed, it will not affect the performance of the device. Such devices are considered symmetrical. According to the polarity of its "channel" (working carrier), MOSFET can be divided into two types: N-type and P-type, usually also called NMOSFET and PMOSFET, abbreviations including NMOS, PMOS, etc.IGBT (insulated gate bipolar transistor), is a composite fully controlled voltage-driven power semiconductor device composed of BJT (bipolar transistor) and MOS. Have the advantages of high input impedance of MOSFET and the low on-voltage drop of the GTR. When the GTR saturation voltage is reduced, the current carrying density is large, but the driving current is large; the MOSFET driving power is small, the switching speed is fast, but the on-state voltage drop is large, and the current carrying density is small. The IGBT combines the advantages of the above two devices, and the driving power is small and the saturation voltage is reduced. In simple terms, an IGBT is equivalent to a thick base PNP transistor driven by a MOS. Figure 1. N-MOSFET Architecture Ⅱ Si IGBT vs SiC MOSFET Since the differences between IGBT and MOSFET in structure, working principle and application range are quite detailed, it is impossible to express clearly in one sentence. Next, we will compare the differences between silicon (Si) IGBTs and silicon carbide (SiC) MOSFETs in detail.The electrical parameters and characteristics of Si IGBT and SiC MOS drivers are quite different. The requirements for driving of SiC MOS are also different from those of traditional silicon devices. They have the characteristics of low on-resistance and small switching loss, which can reduce device loss and improve system efficiency, and more suitable for high frequency circuits. It is widely used in new energy vehicle motor controller, vehicle power supply, solar inverter, charging pile, UPS, PFC power supply and other fields.The difference between the two is mainly reflected in the GS turn-on voltage, GS turn-off voltage, short-circuit protection, signal delay and anti-interference, as follows: Characteristic Si IGBT SiC MOSFET Drive Requirements Switching Frequency Low, >30kHz High, 50~500kHz 1) Use high power gate resistors. 2) Optimize the cooling environment. 3) Improve the efficiency of the DC-DC conversion circuit and reduce the overall loss of driving power. Threshold Voltage 5V-6V 1.6V-4.5V Negative pressure shutdown/Miller clamp to prevent false turn-on Switching Time 300ns 50ns 1) Use digital isolation driver chip, the signal transmission delay can reach 50ns, and it has relatively high consistency, and the transmission jitter is less than 5ns. 2) the low transmission delay push-pull chip is selected. Switching-On Time 15V 15V~22V 1) Priority is given to stabilizing the negative voltage to ensure that the shutdown voltage is stable. 2) A negative voltage clamping circuit is added to ensure that it does not exceed the standard during shutdown. Switching-Off voltage -15V~-5V -5V~0V Short-Circuit Withstand Time <10μs 2~5μs A diode or a resistor string is used to detect short circuits, and the shortest short-circuit protection time is limited to about 1.5μs. CMTI 15kV/μs 100kV/μs 1) The common mode anti-interference ability reaches 100kV/μs to transmit the isolation chip for signal transmission. 2) The optimized isolation transformer design is adopted, and its primary side and the secondary side are shielded to reduce mutual crosstalk. 3) The Miller clamp is used to prevent the influence of the switch of the same bridge arm.   Ⅲ Different Requirements for Si IGBT and SiC MOSFET For a fully-controlled switching device, configuring an appropriate on-off voltage is of great significance for the safety and reliability of the device. Due to the difference between IGBT and MOSFET, the requirements for the two are also different.IGBT is a field-controlled device whose turn-on and turn-off are determined by the voltage between the gate(G) and the emitter(E). The working principle of MOS tube (enhancement mode NMOSFET) is to use VGS to control the amount of "induced charges" to change the condition of the conductive channel, and then to control the drain current. 3.1 ON & OFF State 1) Silicon IGBT: Silicon IGBTs of various manufacturers have the same turn-on and turn-off voltage requirements.· The typical turn-on voltage is required to be 15V.· The shutdown voltage value range is -5V~-15V, and customers can choose the appropriate value according to their needs. The common values are -8V, -10V, -15V.· Prioritize stable positive voltage to ensure stable turn-on.2) Silicon carbide MOSFET: Different manufacturers have different switching voltage requirements:· The turn-on voltage is required to be higher than 22V~15V.· The shutdown voltage is required to be higher -5V~-3V.· Prioritize negative voltage stabilization to ensure stable turn-off voltage.· Increase the negative voltage clamping circuit to ensure that it does not exceed the standard when it is turned off. 3.2 Short-Circuit Protection The switching device has the risk of short circuit during operation, and configuring a suitable short circuit protection circuit can effectively reduce the damage caused by the short circuit during the use of the switching device. Compared to Si IGBTs, SiC MOSFETs have shorter short-circuit withstand times.1) Silicon IGBTThe time of surrender and short-circuit of Si IGBT is generally less than 10μs. When designing the short-circuit protection circuit of it, set the detection delay and corresponding time of short-circuit protection to 5-8μs.2) SiC MOSFETGenerally, the short-circuit withstand capability of SiC MOSFET modules is less than 5μs, and short-circuit protection is required to work within 3μs. A diode or a resistor string is used to detect short circuits, and the protection time is limited to about 1.5μs. 3.3 Interference and Delay 1) The impact of high dv/dt and di/dt on the system.When the switching action is performed under the condition of high voltage and high current, the switching of the silicon carbide MOSFET device will generate high dv/dt and di/dt, which will affect the driver circuit. It is very important to improve the anti-interference ability of the driver circuit for the reliable operation of the system. the following way to achieve.· Add common mode choke coil and filter inductor to the input power supply, which reduce the interference of driver EMI to low voltage power supply.· A low-pass filter is added to the rectification part of the secondary side power supply, which reduce the interference of the driver to the high-voltage side.· Use an isolation chip with a common mode immunity of 100kV/μs for signal transmission.· Optimize the isolation transformer design, and use shielding layer on primary side and secondary side to reduce crosstalk between each other.· Use Miller clamp to prevent the influence of the switch of the same bridge arm. 2) Low transmission delayUsually, the application switching frequency of silicon IGBT is less than 40kHZ, and the recommended application switching frequency of SiC MOSFET is greater than 100kHz. The increase of application frequency makes MOS require the driver to provide lower signal delay time. The transmission delay of the SiC MOSFET drive signal should be less than 200ns, and the transmission delay jitter should be less than 20ns, which can be achieved by the following methods.· Using digital isolation driver chip, the signal transmission delay can reach 50ns, and it has relatively high consistency, and the transmission jitter is less than 5ns.· Select push-pull chips with low transmission delay and short rise & fall time. Due to the conductance modulation effect, the on-state specific resistance of high voltage SiC IGBTs is much lower than that of power SiC MOSs, and does not change much as the blocking voltage rating increases. When the conductance modulation effect is fully exerted, the on-state voltage drop of the IGBT drift region is only related to the bipolar diffusion coefficient and bipolar lifetime of the carriers, and will not change with the increase of the on-current. When the operating temperature changes, the on-state voltage drop of the SiC high voltage IGBT decreases with the increase of the junction temperature. This is mainly because the bipolar lifetime of the extra carriers in the SiC epitaxial layer will increase with the increase of temperature. Although the diffusion coefficient will shrink to some extent with the increase of temperature, the greater prolongation of lifetime will eventually make the the bipolar diffusion length increased, thereby reducing the on-state voltage drop. It is especially true in n-channel devices.This is in sharp contrast to the larger increase in the forward voltage drop of the power MOS at high temperature. Silicon carbide p-channel IGBTs have higher on-state voltage drop than n-channel IGBTs at the same current density due to their larger channel resistance, but their volt-ampere characteristics do not change much with temperature. As for the applications, this is undoubtedly an advantage. Figure 2. Comparison of characteristics between SiC IGBT and power MOS under the Same Condition of Withstand Voltage of 20kV. It is not difficult to calculate from the intersection of the equal power consumption curve in the figure and the on-state characteristic curves of these devices: corresponding to the same power consumption of 300W/cm2, the ratio of the on-state current of the silicon carbide IGBT to the silicon carbide power MOS versus p-channel devices and n-channel devices are different, they are 1.5 and 1.8 at room temperature, respectively, and increase to 2.7 and 3.5 at 225°C, indicating that high-voltage and high-current SiC IGBTs are more suitable for high-temperature applications.In a word, compared with Si IGBT, SiC MOSFET not only improves system efficiency, power density and operating temperature, but also puts forward higher requirements for the driver. In order to make silicon carbide MOSFET better in the system, it is necessary to give SiC MOSFET a appropriate driver.   Ⅳ IGBT Working Principle by Analogy with MOSFET IGBT is a Darlington pair composed of GTR and MOSFET: part of which is MOSFET driver, and the other part is thick-base PNP transistor. Figure 3. IGBT Architecture Its simplified equivalent circuit is shown in the figure below, and RN in the figure is the modulation resistance in the base area of the PNP transistor. It can be clearly seen from this circuit that the IGBT is a composite device of Darlington configuration composed of transistors and MOSFET, where the transistor in the figure is a PNP transistor, and the MOSFET is an N-channel field effect transistor, so the IGBT of this structure is called an N-channel IGBT, and its symbol is N-IGBT. Similarly there are P-channel IGBTs, namely P-IGBTs. Figure 4. Simplified Equivalent Circuit The electrical graphic symbols of the IGBT are shown in the figure. IGBT is a field-controlled device, and its turn-on and turn-off are determined by the voltage UGE between the gate and the emitter. When the gate-emitter voltage UCE is positive and greater than the turn-on voltage UCE (th), a channel is formed in the MOSFET and is a PNP. The N-type transistor provides the base current to turn on the IGBT. At this time, the holes (minority carriers) injected into the N- region from the P+ region modulate the conductance of the N- region, reduce the resistance RN of the N- region, and make the IGBT also has a small on-state voltage drop. When no signal or reverse voltage is applied between the gate and emitter, the channel in the MOSFET disappears, the base current of the PNP transistor is cut off, and the IGBT is turned off. It can be seen that the driving principle of IGBT is basically the same as that of MOSFET.① When UCE is negative: J3 junction is in reverse bias state, and the device is in reverse blocking state.② When UCE is positive: UC< UTH, the channel cannot be formed, and the device is in a forward blocking state; UG> UTH, an N-channel is formed under the insulating gate, and conductance is generated in the N- region due to the interaction of carriers modulation so that the device is conducting forward. Figure 5. Hybrid Switch Using Si IGBT and SiC MOSFET 1) ONThe structure of IGBT silicon is very similar to that of power MOSFET, and the main difference is that JGBT adds a P+ substrate and an N+ buffer layer, in terms of it, one MOS drives two bipolar devices (devices with two polarities). The application of the substrate creates a J junction between the P, and N+ regions of the tube. When the positive gate bias causes the inversion of the P base region under the gate, an N-channel is formed, and an electron flow occurs at the same time, and a current is generated exactly in the manner of a power MOSFET. If the voltage produced by this electron flow is in the range of 0.7V, J1 will be forward biased, some holes will be injected into the N- region, and the resistivity between N- and N+ will be adjusted, which reduces the power conduction the total loss of the pass and initiates a second charge flow. The end result is the temporary emergence of two different current topologies within the semiconductor layer: an electron flow (MOSFET current), and a hole current (bipolar). When UCE is greater than the turn-on voltage UCE(th), a channel is formed in the MOSFET to provide base current for the transistor, and the IGBT is turned on. 2) On-State Voltage DropThe conductance modulation effect reduces the resistance RN and reduces the on-state voltage drop. The so-called on-state voltage drop refers to the tube voltage drop UDS when the IGBT enters the on-state, and this voltage decreases with the rise of UCS. 3) Shut DownWhen a negative bias is applied to the gate or the gate voltage is lower than the threshold value, the channel is disabled and no holes are injected into the N-region. In any case, if the current of the MOSFET decreases rapidly during the switching phase, the collector current decreases gradually. This is because there are still minority carriers in the N layer after the commutation starts. This reduction in residual current value (wake) is entirely dependent on the charge density at turn-off, which in turn is related to several factors, such as the number and topology of dopants, layer thickness and temperature. The decay of minority carriers makes the collector current have a wake waveform. Collector current will cause increased power dissipation and cross-conduction problems, especially on devices that use freewheeling diodes.Considering that the wake is related to the recombination of minority carriers, the current value of the wake should be closely related to the Tc, IC of the chip, and has a close relationship with the mobility of holes. Therefore, depending on the temperature reached, it is feasible to reduce the undesirable effects of this current on the end equipment design. When a back pressure or no signal is applied between the gate and the emitter, the channel in the MOS disappears, the base current of the transistor is cut off, and the IGBT is turned off. 4) Reverse BlockingWhen a reverse voltage is applied to the collector, the junction is reverse biased and the depletion layer expands to the N-region. Because the thickness of this layer is reduced too much, an effective blocking ability will not be obtained, so this mechanism is very important. In addition, if the size of this region is increased too much, the voltage drop will continuously increase. 5) Forward BlockingWhen the gate and emitter are shorted and a positive voltage is applied at the collector terminal, the junction is controlled by the reverse voltage. At this time, the depletion layer of the N drift region is still subjected to the externally applied voltage. 6) LatchICBT has a parasitic PNPN thyristor between the collector and the emitter. Under special conditions, this parasitic device will turn on. This phenomenon increases the amount of current between the collector and the emitter, reduces the controllability of the equivalent MOSFET, and often causes device breakdown problems. The thyristor turn-on phenomenon is known as IGBT latch-up. Specifically, the causes of such defects vary, but are closely related to the state of the devices.   Ⅴ FAQ 1. Are there SiC IGBT?Along with the increasing maturity for the material and process of the wide bandgap semiconductor silicon carbide (SiC), the insulated gate bipolar transistor (IGBT) representing the top level of power devices could be fabricated by SiC successfully. 2. Where are SiC MOSFETs used?The primary automotive applications for SiC power MOSFETs, diodes, and modules are onboard electric vehicle (EV) chargers, DC/DC converters, and drivetrain inverters. Plug-in hybrid EVs and battery EVs (BEVs) use onboard chargers to “refuel” the vehicle battery either at home or at a public charging station. 3. What is SiC MOSFET?Silicon Carbide (SiC) MOSFETs exhibit higher blocking voltage, lower on state resistance and higher thermal conductivity than their silicon counterparts. SiC MOSFETs are designed and essentially processed the same way as silicon MOSFETs. 4. Can MOSFET replace IGBT?Due to the higher usable current density of IGBTs, it can usually handle two to three times more current than a typical MOSFET it replaces. This means that a single IGBT device can replace multiple MOSFETs in parallel operation or any of the super-large single power MOSFETs that are available today. 5. What are the advantages of silicon carbide?Silicon carbide MOSFETs have a critical breakdown strength that is 10x of silicon, and silicon carbide MOSFETs can operate at much higher temperatures, provide higher current density, experience reduced switching losses, and support higher switching frequencies. 6. What are the advantages of silicon carbide (SiC) over silicon (Si)?The advantage of SiC starts in the material itself having a 10x higher dielectric breakdown field strength, 2x higher electron saturation velocity, 3x higher energy bad gap and 3x higher thermal conductivity than Silicon. 7. What is the difference between silicon and silicon carbide?Silicon has a breakdown voltage of around 600V, while silicon carbide can withstand voltages 5-10 times higher. ... Silicon carbide can switch at nearly ten times the rate of silicon, which results in smaller control circuitry. 8. What is SiC in semiconductor?SiC (silicon carbide) is a compound semiconductor composed of silicon and carbide. SiC provides a number of advantages over silicon, including 10x the breakdown electric field strength, 3x the band gap, and enabling a wider range of p- and n-type control required for device construction. 9. Which is better MOSFET or IGBT?When compared to the IGBT, a power MOSFET has the advantages of higher commutation speed and greater efficiency during operation at low voltages. What's more, it can sustain a high blocking voltage and maintain a high current. ... The IGBT is also a three terminal (gate, collector, and emitter) full-controlled switch. 10. Why use an IGBT instead of a MOSFET?The main advantages of IGBT over a Power MOSFET and a BJT are: 1. It has a very low on-state voltage drop due to conductivity modulation and has superior on-state current density. ... It canbe easily controlled as compared to current controlled devices (thyristor, BJT) in high voltage and high current applications. 11. Why is MOSFET preferred?Mosfet provides a very good isolation between the gate and the other two terminals compared to bjt. Mosfet can handle more power compared to BJT. The mosfet has a very low power loss and a high speed. Voltage signals can easily operate a mosfet, so it is used in many digital circuits. 12. Where are MOSFETs used?Power MOSFETs are commonly used in automotive electronics, particularly as switching devices in electronic control units, and as power converters in modern electric vehicles. The insulated-gate bipolar transistor (IGBT), a hybrid MOS-bipolar transistor, is also used for a wide variety of applications. 13. Why IGBT is very popular nowadays?With its lower on-state resistance and conduction losses as well as its ability to switch high voltages at high frequencies without damage makes the Insulated Gate Bipolar Transistor ideal for driving inductive loads such as coil windings, electromagnets and DC motors. 14. How many terminals are in a MOSFET?four terminalsThe MOSFET has four terminals: drain, source, gate, and body or substrate. 15. Why is IGBT bipolar?IGBTs is a bipolar device that utilizes two types of carriers, electrons and holes, resulting from the complex configuration that features a MOSFET structure at the input block and bipolar output, making it a transistor that can achieve low saturation voltage (similar to low ON resistance MOSFETs) with relatively fast. 16. How many types of IGBT are there?two typesInsulated Gate Bipolar Junction Transistor (IGBTs) are normally classified into two types. (ii) Punch Through [PT-IGBT]. These IGBTs are also referred to as symmetrical and asymmetrical IGBTs. These varieties of IGBT differ widely with regard to their fabrication technology, structural details etc. 17. What is full MOSFET?MOSFET stands for metal-oxide-semiconductor field-effect transistor. It is a field-effect transistor with a MOS structure. Typically, the MOSFET is a three-terminal device with gate (G), drain (D) and source (S) terminals. 18. How does an IGBT work as a switch?As defined by being a transistor, an IGBT is a semiconductor with three terminals which work as a switch for moving electrical current. Just as the word “gate” suggests, when voltage is applied to the gate, it opens or “turns on” and creates a path for current to flow between the layers. 19. Can I use transistor instead of MOSFET?It very much depends on the application. BJTs can be cheaper than FETs. This is especially true for high voltage switching where the much larger die area of FETs make them much more expensive. 20. Can IGBT conduct in reverse direction?No. The IGBT cannot conduct current in the reverse direction (from emitter to collector) even with a positive Vge applied to it, because it has a bipolar-type structure. ... However, the gate has no control over this reverse current flow; it is simply the forward biasing of the diode that allows it.

CatalogIntroductionⅠ What is a Microcontroller（MCU）?Ⅱ The History of the Microcontroller (MCU)Ⅲ The Classification and Application of MCUⅣ China MCU Technology and Well-known ManufacturersⅤ  The Basic Functions of MCUⅥ Learning Methods - Using MCUⅦ Six Main Dimensions of MCU Products for Future ImprovementⅧ Programming of MCUⅨ Summary of the MCU Programming EngineerⅩ How to Develop MCU Ⅺ 5 Tips to Solve the Questions About the MCU CrystalⅫ Summary of Chip OperationFAQIntroductionA microcontroller (MCU) is a small computer built on a single metal-oxide-semiconductor (MOS) integrated circuit (IC) chip. A microcontroller is made up of a CPU  (processor core), memory, and programmable input/output peripherals. On chip, a small amount of RAM, as well as ferroelectric RAM, NOR flash, or OTP ROM , is commonly included. Microcontrollers  , in contrast to microprocessors  used in personal computers  or other general-purpose applications, are designed for embedded applications and are made up of a number of discrete chips. This article will delve deeper into the MCU.Ⅰ What is a Microcontroller（MCU）? Microcontroller UnitThe microcontroller unit (MCU) appropriately reduces the frequency and specifications of the CPU  and integrates peripheral interfaces such as memory, counter, USB, A/D conversion, UART, PLC, and DMA. At the same time, even the LCD driver circuit is integrated on a single chip to form a chip-level computer, which can be controlled in different combinations for different applications, such as mobile phones, PC peripherals, remote controls, automotive electronics, industrial stepping motors, machines The control of the arm, etc., can be seen in the MCU.Figure 1 MCU componentsⅡ The History of the Microcontroller (MCU)Microcontroller Unit has a short history, but it has evolved quickly. Its generation and development are roughly synchronized with that of microprocessors  (CPUs). Since Intel Corporation of the United States first introduced 4-bit microprocessors  in 1971, its evolution can be roughly divided into five stages. The following is an overview of the development of Intel's MCU.1971-1976  The initial stage of MCU developmentIn November 1971, Intel introduced the Intel 4004, a 4-bit microprocessor with an integration level of 2000 transistors/chips and equipped with RAM, ROM, and shift registers, which served as the first MCS-4 microprocessor. The Intel 8008 8-bit microprocessor was introduced, followed by other 8-bit microprocessors  from various companies.1976-1980  Low-performance MCU stageThe MCS-48 series, introduced by Intel Corporation in 1976, has a monolithic structure that integrates an 8-bit CPU.  an 8-bit parallel I/O interface, an 8-bit timer/counter, RAM, and ROM on a semiconductor chip. Its addressing range is limited (no more than 4 KB), there is no serial I/O, the RAM and ROM capacity is limited, and the interrupt system is simple, but its functions can meet the needs of general industrial control and intelligent instruments and meters.1980~1983  High-performance MCU stageHigh-performance 8-bit microcontrollers introduced at this stage typically include serial ports, multi-level interrupt processing systems, and multiple 16-bit timers/counters. The capacity of the on-chip RAM and ROM  is increased, and the addressing range can reach 64 KB. A/D conversion interfaces are also available on individual chips. 1983~late 1980s  16-bit microcontroller stage.In 1983, Intel introduced a high-performance 16-bit microcontroller MCS-96  series. The chip integration level was as high as 120,000 transistors/chips due to the use of the most recent manufacturing process.1990sCPUs are developing to a higher level in all directions, such as integration, function, speed, reliability, and application fields. Ⅲ The Classification and Application of MCUMCUs are classified into two types based on their memory type: those with no on-chip ROM  and those with on-chip ROM,  The chip without on-chip ROM  must be used externally with EPROM (typically 8031); the chip with on-chip ROM  is classified as on-chip EPROM (typically 87C51), MASK on-chip mask ROM  (typically 8051), on-chip Flash (typically 89C51), and other types.MCUs are classified into two types based on their intended use: general-purpose and special-purpose. It is classified into4, 8, 16, and 32-bit MCUs based on the width of the data bus and the number of data bytes that can be processed at the same time.Figure 2 MCU product category At present, the most widely used MCU market in China is in the consumer electronics  field, followed by the industrial field and the automotive electronics  market. Consumer electronics  include home appliances, televisions, game consoles, and audio and video systems. Industrial fields include smart homes, automation, medical applications, and new energy generation and distribution. The automotive field includes automotive powertrains and safety control systems. Industrial MCU Industrial MCU products  are primarily used for motor control operation, data acquisition control, and other functions in motor control, instrumentation, low-voltage power distribution, power tools, industrial robots, and other application scenarios.Figure 3 Electric-Vehicle-ChargerThe number of MCU devices is increasing as the complexity of industrial equipment increases. Consider industrial robots: at least ten MCU products  are used in a single industrial robot.Home Appliance MCU MCU is widely used in household appliances, mainly used to realize system control, motor control, panel display control, and other functions.The home appliance market is mainly divided into small household appliances and everyone electricity, small household appliances including kitchen appliances (microwave oven, induction cooker, soybean milk machine, etc.), household appliances (vacuum cleaner, electric fan, electric heater, etc.), personal life small household appliances (electric toothbrush, hairdryer, etc.), everyone electricity mainly for air conditioning, refrigerator, washing machine, and other white appliances.Figure 4 Induction-heating-cooker-app-block-diagramAt the moment, 32-bit MCUs have become the market's mainstream due to their higher specifications and performance, as well as their constantly decreasing cost, and are widely used in automotive electronics.  industrial control/medical, and other fields; however, there are still a large number of application scenarios requiring simple control, and low-value MCUs have cost advantages, so they continue to occupy a large market.BitApplication4Calculator, auto instrument, auto anti-theft device, pager, wireless phone, CD player, LCD dynamic controller, children's toys, scales, chargers, Tire gauge, thermometer, remote control, etc8Electrical appliances, ammeter, motor controller, electric toy machine, pager, fax machine, telephonograph, keyboard and USB, etc16Mobile phones, digital cameras and video recorders, etc32Smart home, IoT, motor and frequency conversion control, security monitoring, fingerprint identification, touch keys, Modem, GPS, STB, Workstation, ISDN telephone, laser printer and color fax machine, etc64Advanced workstation, multimedia interactive system, advanced TV game instrument, advanced terminal, etc.According to IC Insights, the global MCU market is about 16.4 billion dollars in 2019 and could reach about 20 billion dollars by 2023.The scale of China's MCU market was about 25.6 billion yuan in 2019, accounting for about 26% of the global market, with a compound growth rate of 9% from 2015 to 2019.In terms of the global market, the auto circuit accounts for 33% of the global MCU market. According to IC Insights data, the automotive MCU market space will reach $8.1 billion in 2023, the overall growth rate is considerable; At the moment, 32-bit MCUs have become the market's mainstream due to their higher specifications and performance, as well as their constantly decreasing cost, and are widely used in automotive electronics.  industrial control/medical, and other fields; however, there are still a large number of application scenarios requiring simple control, and low-value MCUs have cost advantages, so they continue to occupy a large market.Figure 5  MCU Market StructureFrom the perspective of pattern, the top five global automotive MCU market shares in 2020 were Renesas, NXP, Infineon, Texas Instruments and Microchip, accounting for 87% in total.Ⅳ China MCU Technology and Well-known ManufacturersMCU market is still dominated by overseas leaders, and Chinese high-quality manufacturers are gradually making breakthroughs in the segmented fields, and their share is expected to increase rapidly under the background of accelerated localization in China.The global MCU market is expected to grow further, with the global MCU market size reaching $16.4 billion in 2019 and $20 billion in 2023.On the demand side, improvements in automotive electrification, accelerated IoT  penetration, increased demand for intelligent frequency conversion in home appliances, rapid iteration of wearable devices, and steady growth in industrial control continue to drive the rapid growth of the MCU industry. (Using MCU as an example, the global market compound growth rate from 2020 to 2023 is 7.7 percent, and the market space is expected to be 8.1 billion dollars by 2023)On the supply side, the MCU industry is experiencing a continuous shortage due to the epidemic in 2020. Infineon, NXP.  and ST  , as well as other overseas MCU large factories, have appeared several times to dozens of times the price, with delivery times of more than 50 weeks; persistent shortages are expected to last at least through the end of 2021 and the first quarter of 2022.In terms of circuit barriers, the requirements of automobile circuits in the MCU downstream field are the highest, followed by industrial and home appliance circuits, and the relative requirements of consumer electronics  are slightly lower, according to MCU product environmental temperature, yield, and service life, and other parameters.According to the industry competition pattern, Chinese MCU manufacturers have a low market share, benefit from accelerated replacement due to stock shortages in the short term, and have ample room for improvement in the long term:The global MCU market is more concentrated, with a microchip, ST  MICROELECTRONICS, Renesas, TI, NXP  , Infineon, and other manufacturers occupying more than 80% of the market share; China's MCU market is approximately 25 billion yuan, and the total market share of domestic MCU manufacturers is less than 12%, primarily concentrated in the consumer market, which has ample room for expansion.The shortage of goods leads to the acceleration of the pace of China's MCU manufacturers, in the automotive, industrial, and consumer circuit, the pace of China's MCU certification continues to accelerate. Renesas Electronics - the world's first automotive MCU manufacturer Renesas was founded in 2003 by the merger of Hitachi Semiconductor division and Mitsubishi Electric Semiconductor division. Its main business covers automotive, industrial, communications, and other fields. Renesas is the world's first automotive MCU manufacturer, accounting for 30% of the automotive MCU market in 2020.Renesas MCU has a complete product line covering EV/HEV, powertrain, electric vehicle, vehicle dashboard, vehicle network, chassis control, ADAS, and other application fields.Microchip technology -8 bit MCU main features, acquisition of Atmel to supplement the strength of 32 bit MCUMicrochip Technology Corporation (Microchip) was founded in 1989, Microchip technology is the world's leading supplier of single-chip and analog semiconductors. The company's main business is the microcontroller, memory products, analog interface, and mixed information products, technology licensing, and so on.The products are mainly used in embedded control systems and IoT-related industries, including data processing, Medical Internet + (IoT), smart city, Industry 4.0, intelligent healthcare, etc. Major customers include Intel, Dell, Lockheed Martin, HP, Boeing, etc. STST -ARM architecture MCU king ST was founded in 1987, its products are mainly used in automotive products, computer peripherals, communication systems, consumer products, industrial automation control systems, and other aspects. Its major customers include Apple, blackberry, Bosch, Cisco, Conti, HP, Nokia, Obata, Samsung, and Western Digital.MCU vehicle grade products accounted for 32.13% of the company's revenue. St holds 8.5% of the current MCU market and is the leader in the segmented 32bitMCU  market.ST has been deeply engaged in the automotive semiconductor field for many years, and the company has a complete industrial chain, its products have a very high-cost performance ratio, and occupy a dominant position in the MCU of vehicle regulation level. Its customers include Nissan, Audi, SAIC, Tesla, and many other companies. NXP - the world's leading automotive MCU manufacturer NXP Semiconductor was founded in 2006. It was formerly the semiconductor division of Philips. NXP's main business is MCU, MPU, and other products, which can be widely used in automotive electronics  , industrial control, smart city, smart home, and wearable products. Its MCU/MPU based on the S32 automotive platform has obvious advantages in safety and efficiency and has been adopted by mainstream OEMs around the world.The industry's first crossover MCU was independently developed by NXP: I. MX RT series. Such products have been recognized by many Internet platforms (such as Amazon) for their high integration, cost performance, and security.NXP's acquisition of Freescale (founded by MOTOROLA) in 2015 gives it a deeper presence in the automotive industry. In 2020, 47% of its revenue came from vehicle MCU. At present, the company accounts for 27.8% of the global automotive MCU industry, ranking second in the world. NXP  provides complete semiconductor solutions for intelligent vehicles including automotive entertainment systems, Advanced Driver Assistance Systems (ADAS). Sino Wealth Electronics - China's largest home appliance MCU manufacturer Sino Wealth Electronic Ltd. is an MCU integrated circuit design company, the main products include 8-bit Flash MCU, 8-bit OTP/Mask MCU, 16-bit  DSP , 4-bit OTP/Mask MCU, widely used in household appliances, automotive, industrial control, security, and other fields;In the field of small household appliances, the company's competitors are mainly ABOV from Korea and Holtek from Taiwan. In the field of white household appliances, the company's competitors are mainly from Europe and America, including Renesas, NEC, TI, STM, and so on. Ⅴ The Basic Functions of MCUInternal-function diagramFor most MCUs, the following functions are the most common and basic. The description methods for different MCUs may differ, but the essence is essentially the same.1. Timer: Although there are many different types of Timers, they can be divided into two categories. The first is a Timer with a fixed time interval, which means that its timing is set by the system and cannot be controlled by the user program. The system only provides a few different types of Timers. The user program is given a fixed time interval, such as 32Hz, 16Hz, 8Hz, and so on. Because Timers of this type are relatively common in 4-bit MCUs,they can be used to implement clock, timing, and other related functions.The other type is Programmable Timer. The timing of this type of Timer can be controlled by the user's program. The control methods include the selection of the clock source, the selection of the prescale number, and the setting of the preset number, etc. There are Most MCUs have all three at the same time, and some may have one or both of them. This kind of Timer application is very flexible, and the actual use is also ever-changing. One of the most common applications is to use it to achieve PWM  output.Since the clock source can be freely selected, such Timers are generally combined with the Event Counter.2. IO port: Any MCU has a certain number of IO ports. Without IO ports, the MCU will lose the channel of communication with the outside world. According to the configurable situation of the IO port, it can be divided into the following types:Pure input or pure output : This type of IO port is determined by the MCU hardware design, and can only be input or output, and cannot be set in real-time by software.3. Directly read and write IO port: For example, the IO port of MCS-51 belongs to this type of IO port. When the read IO port command is executed, it is an input port; when the write IO port command is executed, it is automatically an output port.Program programming to set the direction of input and output: the input or output of this type of IO port is set by the program according to the actual needs, the application is more flexible, and can realize some bus-level applications, such as12C bus, various LCD, LED Driver control bus, etc.When using the IO port, this point must be kept in mind: for the input port, there must be a clear level signal to ensure that it cannot be floated (this can be achieved by adding a pull-up or pull-down resistor); and for the output port, the output state level must be Considering its external connection, it should be ensured that there is no source current or sink current in Standby or static state.External interrupts: External interrupts are a basic function of most MCUs. They are commonly used for real-time signal generation, data sampling, and state detection. Rising edge, falling edge, and level triggering are all interrupting methods. In most cases, the external interrupt is handled via the input port. If it is an IO port, the interrupt function will only be enabled when it is set as an input port; if it is set as an output port, the external interrupt function will be automatically closed (with some exceptions in ATMEL's ATiny series, where the output port can also trigger the interrupt function). The application of external interrupt is as follows:Detection of external trigger signals: One is based on real-time requirements, such as thyristor control, detection of sudden signals, and so on, while the other is based on power savings.Measurement of signal frequency:: To ensure that the signal is not missed, an external interrupt is the best option.Decoding data: To reduce design costs in the field of remote control applications, it is frequently necessary to use software to decode various encoded data, such as Manchester and PWM encoding.Button detection and system wake-up: In order for the MCU to enter the Sleep state, it must be woken up via an external interrupt. The most basic form is a button, and the level change is caused by the button's action.4. Communication interface: The communication interface provided by MCU generally includes SPI interface, UART. I2C interface, etc., which are described as follows:SPI interface: This type of interface is the most basic communication method provided by most MCUs. Its data transmission is controlled by a synchronous clock. The signals include SDI (serial data input), SDO (serial data output), SCLK (serial clock), and Ready signal; in some cases, there may be no Ready signal; this type of interface can work in Master mode or Slave mode, the popular saying is to see who provides the clock signal, the party providing the clock is the Master, and the opposite party It is Slaver.UART（Universal Asynchronous Receive Transmit）：It belongs to the most basic asynchronous transmission interface. Its signal lines only have two Rx and Tx lines. The basic data format is: Start Bit + Data Bit(7-bits/8-bits) + Parity Bit(Even， Odd or None) + Stop Bit(1~2Bit). The time occupied by one bit of data is called Baud Rate .For most MCUs, the length of data bits, data check mode (odd check, even check or no check), Stop Bit length and Baud Rate can be flexibly set through program programming. Certainly. The most common way of this type of interface is to communicate with the serial port of the PC.I2C interface: I2C  is a data transmission protocol developed by Philips. It also uses two signals to implement: SDAT (serial data input and output) and SCLK (serial clock). The biggest advantage is that multiple devices can be attached to this bus, and they can be identified and accessed through addresses; one of the biggest advantages of the I2C  bus is that it is very convenient to use software to implement through the IO port, and the data rate of its transmission is completely controlled by SCLK. To control, it can be fast or slow, unlike the UART  interface, which has strict rate requirements.5. Watchdog: Watchdoga basic configuration of most MCUs, can only allow the program to reset it but not close it (some are set when the program is burned in, such as Microchip PIC  series MCUs), while some MCUs are It is determined by a specific method whether it is turned on or not. For example, in Samsung's KS57 series, as long as the program accesses the Watchdog  register, it is automatically turned on and cannot be turned off again. Generally speaking, the reset time of the watchdog can be set by the program. The most basic application of Watchdog  is to provide a self-recovery ability for the MCU to crash due to unexpected failure.Ⅵ Learning Methods - Using MCUThe basic principles and functions of any MCU are similar. The only difference is the configuration and quantity of its peripheral function modules and the instruction system.For the instruction system, although it seems to be different in form, it is only a difference in symbols, and the meanings it represents, the functions to be completed, and the addressing modes are similar.To learn about an MCU, the first thing you need to know is its ROM space, RAM space, number of IO ports, number of timers and timing methods, peripheral function modules (Peripheral Circuit) provided, interrupt sources, operating voltage, and power consumption, etc.After understanding these MCU Features, the next step is to compare the functions of the selected MCU with the required functions of the actual project development and clarify which resources are currently required and which are not used in this project.For the functions that need to be used in the project but are not provided by the selected MCU, it is necessary to carefully understand the relevant information of the MCU, to use an indirect method to achieve it. For example, the developed project needs to communicate with the COM port of the PC, and If the selected MCU does not provide a UART  port, it can be implemented through external interrupts.For the resources needed for project development, you need to carefully understand and read the Manua*, while for the unneeded function modules, you can ignore or browse. For MCU learning, the application is the key and the main purpose.For beginners or designers who use this MCU for the first time, they may encounter a lot of ambiguous descriptions of the functions of the MCU. For this kind of problem, there are two ways to solve it, one is to write a special verification program to understand the functions described in the data; the other can be ignored for the time being. Leave it to modify and improve when debugging. The former method is suitable for projects with loose time and beginners, while the latter method is suitable for those who have some experience in single-chip development or when the project schedule is more urgent.Don't take the time to learn the command system in particular. The instruction system is simply a logical description symbol. During programming, you can only check the relevant instructions in accordance with the logic requirements of the program. As your programming skills improve, you will become more proficient in the instruction system.Ⅶ Six Main Dimensions of MCU Products for Future ImprovementStronger computing performance: MCU towards 500Mhz main frequency, MPU increase more processor cores;Additional wireless connection functions: More RF modules have been integrated.Low power consumption, high energy efficiency ratio: integrated analog chip, and low power analog peripheralsContinued support for hardware accelerators: high integration of algorithms and toolsSafety: improve anti-interference ability and safetyCost-effective: reduce costⅧ Programming of MCUThe programming of MCUs and PCs differ significantly. Although C-based MCU development tools are becoming more popular, assembly language remains the most concise and efficient programming language for designers who are efficient program code and like to use assembly.Circuit diagram to build your own microcontroller programmerThe basic framework for MCU programming is roughly the same, divided into the initialization part (the biggest difference between MCU programming and PC programming), the main program loop body, and the interrupt handler. as shown below:1.Initialization: The most basic and important step in the design of all MCU programs is an initialization, which generally includes the following:Mask all interrupts and set the stack pointer to In general, the initialization section does not want any interruptions to occur.Clearing the system's RAM and displaying the Memory: Although it is not always necessary, it is recommended to develop good programming habits for the sake of reliability and consistency, particularly to avoid accidental errors.IO port initialization: Set the input and output modes of the relevant IO port based on the project's application requirements. Set the pull-up or pull-down resistance for the input port, and the initial resistance for the output port.Interrupt setup: Enable and set interrupt trigger conditions for all interrupt sources required by the project, and close unnecessary interrupts that are not used.Initialization of other functional modules: For all peripheral functional modules of MCU that need to be used, corresponding Settings must be carried out according to the application requirements of the project. For example, Baud Rate, data length, verification mode and Stop Bit length should be set for communication of UART  , and clock source should be set for Programmer Timer. Frequency and Reload Data, etc.Initialization of parameters: after completing the initialization of MCU hardware and resources, the following is the initialization of some variables and data used in the program. This part of initialization needs to be designed according to the specific project and the overall arrangement of the program. For some applications that use EEPROM to store the number of prefab items, it is recommended to copy the relevant data to THE RAM of MCU during initialization to improve the speed of data access and reduce the power consumption of the system (in principle, access to the external EEPROM will increase the power consumption of the power supply).2.Main program loop body: Most MCUs run continuously for a long time, so their main program bodies are basically designed in a looping manner. For applications with multiple working modes, there may be many Each loop body is converted between each other through state flags. For the main program body, the following modules are generally arranged:Calculation procedures: Calculation procedures are generally time-consuming, so it is strongly opposed to processing in any interrupt, especially multiplication and division operations.Processing programs with low or no real-time requirements;Display transfer program: mainly for applications with external LED and LCD Driver.3. Interrupt handler: The interrupt program is mainly used to handle tasks and events with high real-time requirements, such as detection of external sudden signals, detection, and processing of buttons, timing counting, LED display scanning, etc.Under normal circumstances, the interrupt program should keep the code as concise as possible. For functions that do not need to be processed in real-time, the trigger flag can be set in the interrupt, and then the main program executes the specific transaction - this is very important, especially for low-power, low-speed MCUs, is necessary to ensure timely responses to all interrupts.4. There are various MCU processing methods for various task bodies.For example, for low-speed, low-power MCU (Fosc=32768Hz) applications, considering that such projects are handheld devices and use ordinary LCD, the response to buttons and display response requires high real-time performance, so generally Timed interrupts are used to process button actions and data display; for high-speed MCUs, such as Fosc>1MHz applications, since the MCU has enough time to execute the main program loop body at this time, it can only be interrupted at the corresponding Various trigger flags are set in the program, and all tasks are executed in the main program body.5. In MCU programming, special attention should be paid to:Avoid situations where the same variable or data is accessed or set in both the interrupt and the main body. The effective prevention method is to arrange the processing of such data in a module, and decide whether to execute the relevant operation of the data by judging the trigger flag; In other bodies (mainly interrupts), only the trigger flag is set where the processing of the data is required. This ensures that data execution is predictable and unique.Ⅸ Summary of the MCU Programming EngineerTo develop a good habit of summarizing, summarizing is not only a summary of their learning, but also a review and deepening of the learning process, but also to avoid the second error.Before writing the program, we should have a solid understanding of the project so that we can start with a solid idea and a general framework. It is critical to consider the layout and what makes the most sense. To determine which module should be completed first, specific steps for the module, how to name each function, and the relationship with other modules. Take a piece of paper and scribble down significant progress.For C language modular programming, we should first divide each module, a module programming, determine a sequence, and then write the next module based on the success of the previous one. When it comes to header files, write the module's header file after you've finished writing the module.Do not ignore the fact that the program must be unreasonable to comprehend its origins and find a solution. When looking for a source, it should be pertinent; you can search for relevant data on the Internet or consult with others. For example, the primary function of another project was incorporated into this project. Some functions are named multiple times. Step by step analysis of the cause, also according to the experimental phenomenon. When defining the port, the incorrect interface was selected. When you can't solve a problem, it's sometimes good to take a break. Things can go wrong no matter how simple they seemThe problems of code utilization efficiency, anti-interference, and MCU reliability continue to plague MCU application development. Ⅹ How to Develop MCU 1How to reduce program bugsThe following are the over-arching management parameters that should be considered during system operation in order to reduce program bugs.Physical parameters: These are primarily system input parameters that include excitation parameters, acquisition and processing operating parameters, and result parameters at the end of processing.Resource parameters: These are primarily the resources of the system's circuits, devices, and functional units, such as memory capacity, storage unit length, and stacking depth.These application parameters are frequently expressed as the application conditions of some single-chip microcomputers and functional units. The term "process parameter" refers to a parameter that changes in an orderly manner during the system's operation.2How to improve the efficiency of C language programming codeIt is an inevitable trend of the development and application of MCU to use C language to design MCU. If you are programming in C, it is best to be familiar with the C compiler you are using to achieve maximum efficiency. First test the number of statement lines in the assembly language corresponding to each C language compilation, so that you can clearly know the efficiency. When programming in the future, use the statement with the highest compilation efficiency. Each C compiler will have certain differences, so the compilation efficiency will also be different. The code length and execution time of an excellent embedded system C compiler is only 5-20% longer than the same functional degree written in assembly language.C language can be used for complex and time-critical projects, but the premise is that you are very familiar with the C language and C compiler of the MCU system and that you pay special attention to the data types and algorithms that the C compiler system can support. Although C is the most commonly used high-level language, the C language compilation system varies due to MCU manufacturer differences, particularly in the operation of some special function modules. As a result, if you don't understand these features, you'll have a lot of trouble debugging, which will result in lower execution efficiency than assembly language.3 How to Solve the MCU Anti-Interference ProblemThe most effective way to prevent interference is to remove interference sources and cut off interference paths, but this is often difficult to do, so we can only conclude that MCU's anti-interference ability is insufficient. While improving the anti-interference capability of hardware systems, software anti-interference has received increasing attention due to its flexible design, ability to save hardware resources, and high reliability.As for the program run fly, in fact, can also use software trap and watchdog to pull the program back to reset state, so the MCU software anti-interference is the most important to deal with the reset state.In most cases, MCU will have some sign registers that can be used to determine the reason for the reset; alternatively, you can bury some tokens in RAM yourself. Different reset causes can be determined in each program reset by judging these signs. You can also use different flags to jump directly to the corresponding program. In this manner, the program will run indefinitely, and the user will be unaware that it has been reset.4How to test the reliability of the MCU systemWhen a MCU system design is completed, there will be different test items and methods for different MCU system products, but some must be tested:lTest the completeness of the software functions of the MCUlPower-on and power-off testlAging testlTests such as ESD and EFT Sometimes, we can also simulate the damage that may occur in human use. For example, the contact port of the MCU system is intentionally rubbed with the human body or clothing fabric, thereby testing the antistatic ability. Use a high-power electric drill to work close to the MCU system to test the anti-electromagnetic interference ability.To sum up, the MCU has become an important aspect of the development and application of the computer.Most of the functions that must be realized by analog circuits or digital circuits in the past can now be realized by software methods using a single-chip microcomputer. This control technology in which software replaces hardware is also called micro-control technology, which is a revolution of traditional control technology.In addition, in the process of development and application, we must master the skills and improve the efficiency, so as to facilitate its wider use.Ⅺ 5 Tips to Solve the Questions About the MCU CrystalCrystal oscillator for MCUCommon causes of the crystal can not vibratePCB wiring error;Microcontroller quality issues;Crystal vibration quality issues;The load capacitance or matching capacitance does not match the crystal oscillator or the capacitor quality is incorrect;PCB board damp, resulting in impedance mismatch and inability to vibrate;The crystal oscillator circuit is too long;There is a line between the feet of crystal;Influence of peripheral circuit.You are advised to rectify faults one by one as follows: 1Remove the possibility of circuit error so that you can compare the recommended circuit of the corresponding type of microcontroller.2 Rule out the possibility of poor peripheral components; because peripheral components are nothing more than resistance and capacitance.3Rule out the possibility of using a crystal oscillator as a stop oscillator because you will not be experimenting with just one or two crystal oscillators.4Try changing the capacitor at both ends of the crystal; perhaps the crystal oscillator will begin to vibrate; please refer to the crystal oscillator capacitor size instructions.5In PC  B wiring, crystal oscillator circuit wiring should be as short as possible and as close to IC as possible, not between crystal oscillator feet. Ⅻ Summary of Chip OperationThe operation of the chip is mainly the operation of the registers in the chip. The registers in the chip have their unique address mapped on the memory, which is the operation of the corresponding address. To learn the chip, first look at the sequence diagram, then understand the corresponding registers, understand how to operate, define the required port (the program can recognize), write and read the operation program.Cross-sectional-views-of-chip-operationHow data is written to the chip, how it is read out, and through which port it is input or read.When connecting a chip through a bus, the first step is to understand the protocol of the bus. The chip connected to the I2c bus is controlled by the bus.1One 74HC595 lattice is used for column selection, and the other two are used for color selection. The lattice is equivalent to a set of diodes.The diode lights up only when one end is switched to a high level and the other to a low level. Just one end of the selection of different, bright different colors.Timer working mode selection: Set timer T1 in the high four digits and timer T0 in the low four digits. Then the last two characters of each mode set the working mode. When using interrupts, note that after entering the interrupt, the reset should be reset.2Serial port transceiver: Baud rate is generally set in mode 2 (automatic reloading initial value) because different devices have different data processing capabilities, the baud rate is set mainly to take care of low-speed devices and for communication between each other. The interrupt flag bit should be cleared by the software. When setting the serial port interrupt, either sending or receiving can enter the interrupt function, so pay attention to setting the interrupt function. (Self-sense generally sets a function, as the upper machine or lower machine).If you send interrupts, you have to figure out how to enter interrupts the first time, so you send them once and then you can enter interrupts. Only one byte can be sent at a time, and only after TI is set to one can the next byte be sent.3Pcf8591ad conversion, there are four channels of input, read PC  F8591, which channel, read is that channel input voltage, after the conversion of data stored in the chip, then read. Read to write the address of the chip, the son writes device address (0 x40 | channel number) and then reads the data.4Da conversion is to write the device address into the chip first, then write the sub-address (0x40) and then write the digital quantity to be converted. Device address chip information is introduced.5For the liquid crystal display, write data display, he will always display, do not continue to refresh, to change, only re-input.6For THE DS1302 clock chip, reading data is read out of the first data at the falling edge of the eighth clock when writing data, and then prepare for the next output. Pay attention to the writing of the program, but also pay attention to the position of the return value.7In Ds1302, the register is specified first, and then data is written to it. The registers on the chip data indicate the address. 8Initialization is best to write, in case you forget later. When reading or writing, the first operation is the lowest or highest bid, which can be judged according to the sequence diagram.9For the infrared transceiver, receiving, he is according to the length of time between the two falling edges to determine the high level or low level, write a program, first with the timer to determine the length of time, save, and then into binary (the program written to see more, very good).10Stepper motor: mainly used as switches, stepper motor torque decreases with the increase of speed. It is mainly used for automatic feeding of parts processing on machine tools. It can also be used in high-precision control places.Stepper motor is an open-loop control element stepper motor that converts electric pulse signal into angular displacement or linear displacement. In the case of the overload, motor speed, stop position depends only on the pulse signal frequency and pulse number, and are not affected by load change, when the stepper driver receives a pulse signal, it is driving a stepper motor according to set the direction of a fixed Angle, known as the "step Angle", its rotation is based on the Angle of the fixed step by step. The angular displacement can be controlled by controlling the number of pulses to achieve accurate positioning. At the same time, the speed and acceleration of the motor can be controlled by controlling the pulse frequency, achieving the purpose of speed regulation.11Servo motor : Servo motor refers to the engine that controls the operation of mechanical components in a servo system. It is an indirect transmission device for auxiliary motors. Servo motors can control speed, position accuracy is very accurate, voltage signal can be converted into torque and speed to drive the control object. Servo motor rotor speed is controlled by the input signal, and can respond quickly, in the automatic control system, used as an executive element, and has the characteristics of mechanical and electrical time constant is small, high linearity, starting voltage, etc., can receive the electrical signal into the motor shaft angular displacement or angular velocity output. It is divided into DC and AC servo motors. Its main characteristic is that when the signal voltage is zero, there is no rotation phenomenon, and the speed decreases uniformly with the increase of torque.12Chinese Characters overview: To output Chinese characters on display or printer, Chinese characters are designed into a dot matrix graph according to graphic symbols, and corresponding dot matrix codes (glyphs) are obtained.The unified encoding for the representation of Chinese characters in the computer is called the internal code (such as national code), and the internal code is unique (equivalent to the id number of the character). The encoding of Chinese characters formed to facilitate the input of Chinese characters is the input code, which belongs to the external code of Chinese characters. The input code varies with the encoding mode and is diverse. The Chinese character code formed for displaying and printing Chinese characters is the character code, and the computer finds the character code in the character library through the character code and realizes its conversion.Machine code: According to the GB code, each Chinese character has a certain binary code, but this code will conflict with THE ASCII code when handled internally by the computer. To solve this problem, the first byte of each GB code is incremented by 1. Because ASCII code only uses 7 bits, the "1" on the first digit can be used as a symbol to identify Chinese character codes. When the computer processes the code with the first digit of "1", it will be interpreted as the information of Chinese characters, and when it processes the code with the first digit of "0", it will be interpreted as the ASCII code. After such processing, the national code (internal code) is the machine's internal code.If put this "mouth" word graphic "." With "0" instead, you can very vividly get the "mouth" glyphs :0000H 0004H 3FFAH 2004H2004H 2004H2004H 2004H2004H 2004H2004H 2004H 3FFAH 2004H 0000H 0000H. Computer to output "mouth", find shows that character first address, according to the "mouth" machine code after calculation, to find a "mouth" glyph code, and then according to the glyph code (to) in binary character generator, in turn, scan control on the screen, which is where the "0" of the binary empty, is a place where "1" swept out of the window, Then you get the character graph of the mouth.Chinese characters are arranged according to the order of national standard codes and stored in the memory in the form of binary files, which constitute the Chinese character font library, also known as the Chinese character font library, called the Chinese character library1312864 liquid crystal: Each display point corresponds to a binary number, with 1 indicating on and 0 indicating off. The RAM that stores this lattice information is called the display data memory. To display a graph or Chinese character is to write the corresponding lattice information into the corresponding storage unit.When the horizontal address = 0FH, it will be reset to 00H, but it will not automatically add one to the vertical address. Therefore, when writing multiple data in a row, the program needs to determine whether the vertical address needs to be reset14GDRAM: Drawing display RAM provides 128×8 bytes of memory space. When changing the drawing RAM, the horizontal and vertical coordinate values are successively written, and then two bytes of data are written to the drawing RAM. The address counter (AC) will automatically increment the horizontal address (X address) and reset to 00H when the horizontal address is 0XFH. Vertical addresses will not be carried automatically plus 1. The drawing display must be turned off during writing to the drawing RAM,For C, a defined variable is automatically allocated space and its address is the name of the variable. Through this name, the data can be recruited in memory, and the new data can be obtained through an operation. In assembly, the programmer needs to define the storage space and send the data to the accumulator for operation, and the programmer needs to operate every step. In C, this is done by the compiler.FAQ1. What is the main function of microcontroller?Microcontroller is a compressed micro computer manufactured to control the functions of embedded systems in office machines, robots, home appliances, motor vehicles, and a number of other gadgets. A microcontroller is comprises components like - memory, peripherals and most importantly a processor.2. What is an example of a microcontroller?The examples of 8-bit microcontrollers are Intel 8031/8051, PIC1x, and Motorola MC68HC11 families. The 16-bit microcontroller performs greater precision and performance as compared to the 8-bit.3. What are the elements of a microcontroller?Therefore, the microcontroller must also satisfy the five basic elements of input, calculation, storage, output, and control. These are called five elements of microcontrollers.4. Which is best microprocessor or microcontroller?If you need access to large amounts of really fast memory then a microprocessor is likely your best option. A microcontroller is already embedded with memory so the memory choices are fewer than with a microprocessor. The maximum amount of FLASH memory available with most microcontrollers is usually around 2MB.5. What is difference between BIOS and CMOS?The BIOS is the program that starts a computer up, and the CMOS is where the BIOS stores the date, time, and system configuration details it needs to start the computer. ... CMOS is a type of memory technology, but most people use the term to refer to the chip that stores variable data for startup.6. Is CMOS a RAM or ROM?RAM and ROM are the products, but Complimentary Metal Oxide Semiconductor (CMOS) is the process they are built in. CMOS uses two different types of transistors to achieve a lower overall power consumption.7. Whats an RTC battery?The Real Time Clock (RTC) battery provides power for the internal clock/calendar and for maintaining system configuration settings. This error can occur when a machine has been left turned-off for an extended period of time (approximately one to four months), and it is the result of a depleted RTC battery.            

Introduction As a power semiconductor device, IGBT(insulated-gate bipolar transistor) is widely used in the fields of rail transit, smart grid, industrial energy saving, electric vehicles and new energy equipment. It has the characteristics of energy saving, convenient installation and easy maintenance, and stable heat dissipation. It is the core device for energy conversion and transmission. A brief overview, IGBT can be said to be a combination of MOSFET(metal–oxide–semiconductor field-effect transistor) and BJT(bipolar junction transistor). That is, it combines the gate voltage control transistor (high input impedance) of the MOSFET, and uses the dual carriers of the BJT to achieve the purpose of large current (voltage-controlled bipolar device). So what is the internal structure of such a combination? This article will explain in detail with examples. What is IGBT and Its Applications Catalog Introduction Ⅰ IGBT Module Explained Ⅱ IGBT Internal Structure Ⅲ IGBT Internal Current Flow Ⅳ How to Disassemble IGBT Module? Ⅴ FAQ Ⅰ IGBT Module Explained The model of the IGBT module to be disassembled as an example is: FF1400R17IP4. The appearance and equivalent circuit of the module are shown in Figure 1. The length, width and height of this module are: 25cmx8.9cmx3.8cm. The module contains two IGBTs, which are what we often call half-bridge modules. The rated voltage and current of each IGBT are 1.7kV and 1.4kA. Figure 1. FF1400R17IP4 Part 8, 9, 10, 11, and 12 are power terminals and need to be connected to a power circuit.1, 2, 3, 4, and 5 are auxiliary control terminals, which need to be connected to the gate drive circuit.6 and 7 are NTC thermistors, used for temperature detection or over-temperature protection.After having a general understanding of its structure, what can we do with such a black module with this structure? Take an example around us: new electric vehicles, everyone should be familiar with it. Three such black modules can be used as a three-phase motor driver. If it is equipped with a battery, it can drive an electric bus. Of course, this module is also used in many other applications. Figure 2. IGBT in Electric Bus   Ⅱ IGBT Internal Structure After having a preliminary understanding of the external structure and application of the IGBT module, let us enter the subject of this article to see what the inside of this high-tech black module looks like. Figure 3 is the internal picture of the IGBT module with the black casing removed. It should be noted that the most common copper and aluminum are inside the IGBT module. Figure 3. IGBT Internal Structure Figure 4 is a cross-sectional view of the IGBT module. If the black casing and external connection terminals are removed, the IGBT module mainly contains 3 components, the heat dissipation substrate, the DBC substrate and the silicon chip (including the IGBT chip and the Diode chip), and the rest is mainly solder layers and interconnecting wires are used to connect IGBT chips, Diode chips, power terminals, control terminals and DBC(Direct Bond Copper). Below we will briefly introduce each part. Figure 4. IGBT Section View ① Heat Sink SubstrateThe bottom of the IGBT module is the heat dissipation substrate, the main purpose is to quickly transfer the heat generated by the IGBT switching process. Since copper has better thermal conductivity, the substrate is usually made of copper, and the thickness of it is 3-8mm. Of course, there are also substrates made of other materials, such as aluminum silicon carbide (AlSiC), both of which have their own advantages and disadvantages. ② DBCDBC (Direct Bond Copper) is a ceramic surface metallization technology, which contains 3 layers. Have a ceramic insulating layer in the middle and a copper clad layer above and below respectively, as shown in Figure 5(a). Simply put, it is to cover both sides of an insulating material with a copper layer, and then etch a pattern that can carry current on the front side, and the back side must be directly soldered to the heat sink substrate. Figure 5. BDC Base vs PCB The main function of DBC needs to ensure the electrical insulation capacity between the silicon chip and the heat dissipation substrate and good thermal conductivity, while also providing a certain current transmission capacity. The DBC substrate is similar to a 2-layer PCB circuit board. The insulating material in the middle of the PCB is generally FR4, while the commonly used ceramic insulating materials for DBC are aluminum oxide (Al2O3) and aluminum nitride (AlN).For the IGBT module analyzed in this article, there are 6 DBCs inside, and each has 4 IGBT chips and 2 Diode chips. Among them, 2 IGBT chips and 1 Diode chip are used as the upper tube, and the rest are used as the lower tube. As shown in Figure 6. Figure 6. DBC Diagram and Equivalent Circuit ③ IGBT ChipThe IGBT chip model used inside the module is: IGCT136T170. The manual can be downloaded from Infineon official website. Figure 7 shows the top view and basic parameters of the IGBT chip. The gate and emitter of the IGBT are above the chip (front side), and the collector is below (back side). The thickness of the chip is 200um. After the IGBT powers on, the current flows from bottom to top, so the IGBT of this structure can also be called a vertical device. Chip Type VCE ICn1) Die Size IGC136T170S8RH2 1700A 117.5A 17.72×7.7mm2 Figure 7. IGBT Chip Diagram If you make a vertical cut on the 200um chip, you can get the internal structure shown in Figure 8, which is a combination of P-type or N-type semiconductors with different doping. Figure 8 shows the well-known equivalent circuit of an IGBT, which is usually understood as a MOS-controlled PNP transistor. When start to learn about power electronics, you may feel that this picture is a bit strange. Why not draw the collector on the top and the emitter on the bottom? Until you understand that the IGBT current flows from bottom to top, it is not difficult to explain. Figure 8. IGBT Chip Structure and Equivalent Circuit Let’s have a general understanding of the electrical parameters of this IGBT chip. This chip can pass a DC current of 117.5A at 100°C. It can be seen from Figure 4 that a single IGBT device inside the module contains a total of 12 IGBT chips, so the total current is: 117.5*12=1412A, which is basically the same as the 1400A rated current in the IGBT module manual.In order to ensure the current sharing effect between IGBT chips, a 11.5Ω resistor has been integrated inside the gate of each chip. At the same time, considering the current sharing between the DBCs, the two chips on each DBC share a gate resistor externally, as shown in Figure 10. When measuring it with a multimeter, and the resistance is about 4.13Ω. You can calculate it in conjunction with Figure 9 to see if it is consistent with the 1.6Ω in the IGBT module manual. Of course, you can refer to the official manual for more detailed parameters of the IGBT chip. Figure 9. IGBT Equivalent Circuit ④ Diode ChipFigure 10 is a top view of the Diode chip, with the anode on the front and the cathode on the back. The current direction of the diode is from top to bottom, which is exactly the opposite of the current direction of the IGBT. The rated current of the diode chip is 235A, and each IGBT is composed of 6 diodes in parallel, and the total current can reach 1410A, which is basically the same as the 1400A in the module manual. The thickness of diode chip is the same as IGBT, it is also 200um. For more detailed parameters of the diode chip, please refer to the official manual. Chip Type VR IFn1) Die Size SIDC130D170H 1700A 235A 16.3×8mm2 Figure 10. Diode Diagram Such a thin semiconductor material can have kV voltage and hundreds of amperes of current on and off, it’s amazing. This is why the price of high-power semiconductor devices is so very expensive.The upper copper layer interconnection of IGBT chip, Diode chip and DBC is generally realized by bonding wires. Commonly used bonding wires are aluminum wire and copper wire. Among them, the aluminum wire bonding process is mature and the cost is low, but the electrical and thermodynamic properties of the aluminum wire bonding are poor, and the expansion coefficient mismatch is large, which affects the service life of the IGBT. The copper wire bonding process has the advantages of excellent electrical and thermodynamic properties, high reliability, and is suitable for modules with high power density and efficient heat dissipation.   Ⅲ IGBT Internal Current Flow After having a basic understanding of the internal structure of the IGBT module, let us go back and interconnect all the above components to see how the current flows inside the IGBT module. Here we take the upper tube IGBT in one of the DBCs as an example to illustrate the current flow. Red represents the current direction of the upper tube IGBT (S1 and S2), and blue represents the current direction of the diode D1. Figure 11(b) is a left cross-sectional view and a schematic diagram of the current direction of the module of Figure . Figure 11(a). IGBT Current Flow Figure 11(b). IGBT Current   Ⅳ How to Disassemble IGBT Module? Some friends may be curious about how to disassemble this module, but it is actually very simple. You only need to prepare two screwdrivers and a small hammer. Figure 12. IGBT Disassemble Step 1: Unscrew the 4 screws at the bottom of the IGBT module.Step 2: Use a flat-blade screwdriver to pry open all the terminals on the front of the IGBT module. This step is very important. It is necessary to ensure that all the terminals after being pried are vertical to the module substrate.Step 3: You need to fix the IGBT in one place, or use a flat-blade screwdriver to align any position of the connection between the plastic casing of the IGBT module and the substrate, hit the screwdriver with a hammer, and pry the casing from the substrate with the screwdriver. After prying open one position, place something on it, and then pry another position, repeat that, after slowly prying open, just pry open with your hands directly.   Ⅴ FAQ 1. What is IGBT module?An IGBT is a is power semiconductor die and is the short form of insulated-gate bipolar transistor. ... An IGBT power module functions as an electronic switching device. By alternate switching direct current (DC) can be transformed to alternating current (AC) and vice versa. 2. How does IGBT module work?The IGBT combines the simple gate-drive characteristics of power MOSFETs with the high-current and low-saturation-voltage capability of bipolar transistors. The IGBT combines an isolated-gate FET for the control input and a bipolar power transistor as a switch in a single device. 3. What is the purpose of IGBT?The IGBT combines, in a single device, a control input with a MOS structure and a bipolar power transistor that acts as an output switch. IGBTs are suitable for high-voltage, high-current applications. They are designed to drive high-power applications with a low-power input. 4. How many layers are there in IGBT?Working of IGBTIGBT is constructed with 4 layers of semiconductor sandwiched together. The layer closer to the collector is the p+ substrate layer above that is the n- layer, another p layer is kept closer to the emitter and inside the p layer, we have the n+ layers. 5. Which are the terminals of IGBT?The three terminals of IGBT are Gate, Collector and Emitter. 6. How many terminals Mosfet has?four terminalsThe MOSFET has four terminals: drain, source, gate, and body or substrate. 7. What is the function of injecting layer in IGBT?The p+ substrate is also called injector layer because it injects holes into n- layer. The n- layer is called drift region. The next p layer is called the body of IGBT. The n- layer in between the p+ & p region serves to accommodate the depletion layer of pn- junction i.e. J2. 8. Can I replace IGBT with MOSFET?Due to the higher usable current density of IGBTs, it can usually handle two to three times more current than a typical MOSFET it replaces. This means that a single IGBT device can replace multiple MOSFETs in parallel operation or any of the super-large single power MOSFETs that are available today. 9. What are the three terminals of an IGBT and how does it function?The IGBT (insulated gate bipolar transistor) is a three-terminal electronic component, and these terminals are termed as emitter (E), collector(C) and gate(G). Two of its terminals namely collector and emitter are associated with a conductance path and the remaining terminal 'G' is associated with its control. 10. What is an IGBT describe its construction?IGBT – Working, Types, Structure, Operation & Applications. ... The IGBT (Insulated Gate Bipolar Transistor) takes the best parts of both BJT and MOSFET into a single transistor. It takes the input characteristics (high input impedance) of MOSFET (Insulated Gate) and the output characteristics of BJT (Bipolar nature). 11. How does IGBT convert DC to AC?The IGBT act as a switch (when a signal is applied to the gate, they turn on and then turn off when the signal is removed). By closing Q1 and Q4, a positive d.c. supply is applied to the load. Q2 and Q3 will result in a negative d.c. supply across the load. 12. What is the advantage of IGBT?The main advantages of IGBT over a Power MOSFET and a BJT are: It has a very low on-state voltage drop due to conductivity modulation and has superior on-state current density. So smaller chip size is possible and the cost can be reduced. 13. What is drift layer in IGBT?The drift region (electric field or movement of charge) of the IGBT works as a base of the PNP transistor . The current gain of the transistor depends upon the width and doping level of the transistor. 14. What is the structure of IGBT?The structure of IGBT is very much similar to that of PMOSFET, except one layer known as injection layer which is p+ unlike n+ substrate in PMOSFET. This injection layer is the key to the superior characteristics of IGBT. Other layers are called the drift and the body region. The two junctions are labeled J1 and J2. 15. What are the advantages of IGBTs?Advantages of IGBT:Simple drive circuitLow on-resistanceHigh voltage capacityFast switching speedEasy of driveLow switching lossLow on stage power dissipationLow gate drive requirement 16. Why IGBT is very popular nowadays?With its lower on-state resistance and conduction losses as well as its ability to switch high voltages at high frequencies without damage makes the Insulated Gate Bipolar Transistor ideal for driving inductive loads such as coil windings, electromagnets and DC motors. 17. Why diode is used in IGBT?We know that MOSFET or IGBT is a unidirectional device, they only conduct current in forward bias and block the current in reverse bias. ... For this reason, an external diode is connected across the MOSFET or IGBT or SCR to provide a path for reverse current.