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Warm hints: The word in this article is about 3000 words and reading time is about 15 minutes   This article is mainly talking about how to design better electromagnetic compatibility if LCD. Electromagnetic compatibility (EMC) is an inevitable issue in the design of LCDs. If the EMC design is not good, it will cause water ripples and strobe flash problems during the broadcast of the TV. EMC design is actually optimized for the electromagnetic interference generated in the product to meet the EMC standards of countries or regions. It is defined as the ability of a device or system to function properly in its electromagnetic environment and does not constitute unacceptable electromagnetic interference (EMI) to anything in the environment.       Catalog I. Brief Introduction II. Power Module EMC Design III. Main Drive Board EMC Design IV. Tuner Board EMC Design V. Whole Machine EMC Design FAQ   I. Brief Introduction Electromagnetic interference is generally divided into conducted interference and radiation interference. Conducted interference refers to the coupling interference of signals on one electrical network to another electrical network through conductive media. Radiated interference means that the interference source couples (disturbs) its signal to another electrical network through space.   The LCD structure mainly includes a liquid crystal display module, a power supply module, a drive module (mainly including the main drive board and a tuner board), and a key button module. General liquid crystal display modules have been tested by EMC before production. Here mainly introduces the design of the power module, drive module, button module, and the whole machine should pay attention to the electromagnetic interference problem.   EMI (ElectroMagnetic Interference) & EMC (Electromegetic Compatibility)   II. Power Module EMC Design The two main functions of the power supply section are to realize the backlight for driving the LCD screen and to provide DC power for other modules (including the drive module and the button module).   The design of the power module directly affects the entire system. If the design is not good, it will cause large water ripples in the TV. In severe cases, the TV will not be used. At the same time, it will seriously affect the normal use of other nearby equipment.   The power supply of LCDs is based on switching power supplies. The causes of electromagnetic interference problems caused by switching power supplies are complex. When designing the switching power supply, it is necessary to prevent the switching power supply from causing interference to the power grid and nearby electronic equipment. It is also necessary to strengthen the adaptability of the switching power supply itself to the electromagnetic interference environment.   To solve the EMC problem of switching power supplies, the following main measures should be taken into consideration during design:   Soft-switching technology: Inrush current and peak voltage are generated when the switching device is turned on/off. This is the main reason for electromagnetic interference and switching loss in the switch. Soft switching technology is an important method to reduce the loss of switching devices and improve the EMC characteristics of switching devices. This technology is mainly to switch the switching tube in the switching power supply at zero voltage and zero current to effectively suppress electromagnetic interference.   Modulation frequency control: Electromagnetic interference is changed according to the switching frequency, and the interference energy is concentrated on the discrete switching frequency point, resulting in large interference intensity. By distributing the energy modulation of the switching signal over a wide frequency band, a series of discrete sidebands are generated. This spreads out the interference spectrum, and the interference energy is distributed on the discrete frequency band, thereby reducing the electromagnetic interference intensity at the switching frequency point.   Component layout and routing: The components associated with the power input signal and output signal are placed near the corresponding ports to avoid interference due to the coupling path. Put components that are related to each other together to avoid interference caused by long traces.   Also, try to avoid parallel routing of signal lines. If unavoidable, try to increase the line spacing. Or add a ground wire in the middle to reduce the interference between each other.   III. Main Drive Board EMC Design The main driver board of the LCD mainly includes an analog signal portion, a high-speed digital circuit portion, and a noise source DC-DC power supply portion.   Component layout and routing: In the layout, the three parts of the analog signal part, the high-speed digital circuit part, and the noise source DC-DC power supply part should be reasonably separated so that the signal coupling between them is the minimum. In terms of device placement, the principle of associating the devices with each other is as close as possible, so that a good anti-noise effect can be obtained.   DC-DC Power Supply Part and Ground: On printed circuit boards, the power line and ground are the most important. Let analog and digital circuits have their own power and ground paths, respectively. The main means of overcoming electromagnetic interference is grounding.   On the driving board of the LCD, the ground of the power supply section (DC-DC) is mainly separated from other grounds such as the decoding and main chip processing, so as to reduce interference of the power supply on the image display and the television sound.   If there are analog ground and the digital ground when designing the circuit, they should be separated when the printed board is laid. To reduce mutual interference. In the layout of double-layer boards and multilayer PCBs, one layer of copper foil is generally used as a dedicated ground plane. The purpose of this is that this ground serves as a shield.   Integrated chip: In the same integrated chip, the ground is also separated from the analog ground and the digital ground. For example, the AD9883 analog-to-digital conversion chip of the AD company, which is often used as the main driver board of the LCD, can be floor-separated between the ground and digital sections of the analog section of the chip during the PCB design. Finally, connect the two points by a relatively short wire. Or connect the two places with a 1nF bypass capacitor.   Crystal oscillator: The clock circuit in the digital circuit is one of the main electromagnetic interference sources in current electronic products and is the main content of EMC design. Crystal is a strong source of radiation. The internal circuit of the crystal generates a large RF current, so that the ground lead of the crystal cannot sufficiently draw a relatively large Ldi/dt current to the ground plane with little loss, and as a result, the metal housing becomes a monopole antenna. The periphery of the crystal is a radiation field.   Therefore, the crystal oscillator circuit is far away from the interface circuit, such as serial port, address line, and data line. In order to avoid the interface circuit bringing the harmonic signal of the crystal out of the printed circuit board to cause electromagnetic interference. Two legs of the crystal oscillator must be added with an RC filter circuit. At the same time, be sure to connect the metal shell of the crystal to the ground on the printed board. In addition, the crystal is placed as close as possible to the chip pins. The ground is used to isolate the clock area, placing a local ground plane and connecting it to the ground through multiple vias.   Capacitance decoupling: Capacitance decoupling is used to reduce electromagnetic interference. Capacitor decoupling can be divided into three types: overall, partial, and inter-board.   The overall decoupling capacitor operates at low frequencies, providing a stable voltage and current for the entire board. It should be placed close to the printed circuit board power cord and ground. The typical decoupling capacitor value is 0.1μF. The typical value of the distributed inductance of this capacitor is 5μH. The 0.1μF decoupling capacitor has 5μH distributed inductance. Its parallel resonant frequency is about 7MHz. That is to say, it has a better decoupling effect for noise below 10MHz, and it has almost no effect on noise above tens of MHz. So for noise above 20MHz, use a 0.01μF capacitor decoupling.   The local decoupling capacitor makes the supply voltage obtained by the integrated circuit more stable; in addition, the high-frequency noise of the device is bypassed.   The decoupling capacitance between boards refers to the capacitance between the power plane and the ground plane and mainly solves the high-frequency transient current generated in the power supply. A 10~100uF electrolytic capacitor is connected across the input of the power supply. If the position of the printed circuit board is allowed, the anti-interference effect of the electrolytic capacitor with 100uF or more will be better. The lead of the decoupling capacitor can not be too long, generally close to the integrated circuit power supply, the connection should be rougher.   Bead filtering: Bead filtering is applied to all signal inputs (such as YPBPR and VGA) on the motherboard. Magnetic beads are designed to suppress high-frequency noise and spike interference on signal lines and power lines, and also have the ability to absorb electrostatic pulses. It acts as a high-frequency resistor, which attenuates high frequencies. The device allows the DC signal to pass and filter out the AC signal.   When selecting beads, you must pay attention to the following factors:   1. What is the unwanted signal frequency range? 2. Who is the noise source; 3, how much noise attenuation; 4. What is the environmental condition (temperature, DC voltage, structural strength); 5. What is the circuit and load impedance? 6. Is there room to place beads on the PCB board?   The first three can be judged by observing the impedance frequency curve provided by the manufacturer. The three curves in the impedance curve are very important, namely the resistance R, inductive reactance X, and total reactance Z. As shown in Figure 1:     Figure 1: Impedance curve and equivalent circuit topology that reflect the bead resistance, inductive reactance, and total inductance   The total impedance is described by the following formula (1):   Z=(R + 2πFL)   From this curve, beads are selected that have the maximum impedance in the frequency range where attenuation of the noise is desired, and where the attenuation of the signal is as small as possible at low and DC.   Chip beads can affect the impedance characteristics under excessive DC voltage. In addition, if the operating temperature rises too high or the external magnetic field is too large, the impedance of the beads will be adversely affected.   Whether using chip beads or chip inductors is also mainly in applications. Chip inductors are needed in the resonant circuit. When it is necessary to eliminate unwanted electromagnetic interference noise, the use of chip beads is the best choice.   IV. Tuner Board EMC Design The tuner board mainly includes a tuner section and an audio processing section.   When conducting the circuit design of the tuner board part and the layout of the PCB board, it is necessary to pay special attention to the electromagnetic interference problem. The following points must be considered:   （1）First, separate the land of the TUNER section (ie the simulated ground) from the land of the other sections. （2） Be sure to connect the metal shell of TUNER to the ground. The connection points can better eliminate electromagnetic interference. The tuner TUNER inherently has a high-frequency circuit, so it must be shielded. （3）When selecting the interface terminals (such as AV terminal, S-VIDEO terminal, etc.), try to use terminals with good conductivity and strong anti-electromagnetic interference, and also connect the ground of the interface terminal with the earth completely. At the same time also added magnetic beads filter. （4）The signal line should be as short and straight as possible. If it cannot be avoided, fly line transitions can be used. Signal lines should not form a ring. Because the ring is equivalent to the number of turns of the coil, the radiation effect of the ring wiring is the strongest. （5）Try to reduce dead copper in large areas. The solution is to connect them to the ground. If a large area of dead copper forms the antenna, electromagnetic interference will be introduced. （6）Do not run under quartz crystals and under noise-sensitive devices.   The audio processing section should pay special attention to the layout of the printed circuit board, first of all, avoid high-speed signal lines and audio and video lines together. For example, if you connect the clock line SCL and the data line SDA in the I2C bus to the traces of the audio line. Since the clock line SCL and the data line SDA in the I2C bus are constantly changing, they interfere with the sound. Obviously, for example, when you use a TV remote control to switch to a TV channel, you can hear a regular "click, click" sound from the speaker. This may be because of the above issues that were overlooked in the PCB layout.     V. Whole Machine EMC Design   The assembly drawing in the whole machine (taking one of the models as an example) is shown in Figure 2: Figure 2: In-machine assembly drawing of a model that reflects various EMI concerns   The connection line numbered 5 in the figure above is the screen line of the digital panel connection screen. Because the screen line is mainly on the screen data. It will cause a great disturbance to the system. The best way to reduce interference is to use twisted pairs and shielded wires. If it is a TTL screen, the screen line needs to be shielded or a magnetic ring outside the connection line. If on the LVDS screen, you need to use twisted pair, plus a magnetic ring. In order to reduce the screen line to the entire system of electromagnetic interference. With shielded twisted pair, the signal current can flow on the two inner conductors, and the noise current flows in the shield layer, thus eliminating the coupling of the common impedance, and any interference will induce the two conductors at the same time so that the noise cancels.   A magnetic ring is also required on the connection between the power supply and the main control board (referenced 4). The main reason is that the power cord will generate relatively large electromagnetic interference to the motherboard.   A magnetic ring should also be added to the connection between the keypad and the motherboard (referenced 9). The main reason is that there is a constant data change (remote control receiver head) on the keypad which causes electromagnetic interference to the system. Plus magnetic rings can effectively shield electromagnetic interference.   A magnetic ring is added to the audio cable (labeled 10) connected to the speaker to reduce the electromagnetic interference from the audio output to the system. If there is a cable (label 6, 7, 8) between the motherboard and the tuner board, you need to add a magnetic ring on the cable. To reduce the electromagnetic interference between cables.   The magnetic ring added above can be added according to the specific situation and can be determined by repeated experiments.   Use of shields: In general, shields are required for liquid crystal display modules, main control boards (including digital boards and tuner boards), and power supplies.   The main frequency of the main chip is the main cause of electromagnetic interference. Frequency harmonics of the main frequency are most likely to produce electromagnetic interference. In the experiment conducted by EMC, the frequency harmonics of the main frequency had large electromagnetic interference. The main chip must be shielded during design. The main shielding measures include a metal shield on the digital board. Adding a shield is the most effective way to resist electromagnetic interference. However, because of the heat dissipation problem of the driver board and the entire system, it is required that the holes on the shield cover be used to dissipate heat. However, its maximum size must be less than 1/100 of the shortest wavelength of noise.   The shield on the tuner board is mainly shielded from the TUNER section.   The shielding of the power supply section is particularly important. If the shielding of the power supply section is not good, it will cause large interference. This will not lead to conduction. And because the heat of the power supply is very severe, the shield must pay attention to the problem of heat dissipation.   Usually, shields have openings and seams that can cause electromagnetic leaks. As a result, the shielding effect is not good. Solve electromagnetic leaks at joints by using electromagnetic seal gaskets at the joints. The electromagnetic leakage of the opening in the shield is related to the size of the opening, the characteristics of the radiation source, and the distance from the radiation source to the opening. The requirement for shielding is met by designing the size of the opening and the distance of the radiation source to the opening. FAQ   1. What can cause electromagnetic interference? Electromagnetic interference (EMI) is a disturbance caused by an electromagnetic field which impedes the proper performance of an electrical device. EMI can come from man-made or natural sources such as the sun or the Earth's magnetic fields.   2. How do you stop electromagnetic interference? The simplest way to reduce magnetically induced interference is to use twisted pair wires. This applies both for shielded and unshielded cables and for interference caused by shield currents or from other sources. Twisting the wires forces them close together, reducing the loop area and therefore the induced voltage.   3. How do you make electromagnetic interference? Plug both devices into a wall outlet in the same house or building. Since the wall outlets in most houses are tied to the same ground, the ground is a common source of conducted interference, especially from the low frequency hum of an electric motor. Turn on both devices at the same time.   4. Is electromagnetic interference bad for you? There is no doubt that short-term exposure to very high levels of electromagnetic fields can be harmful to health. ... Despite extensive research, to date there is no evidence to conclude that exposure to low level electromagnetic fields is harmful to human health.   5. What are three types of interference? Electromagnetic interference (EMI) Co-channel interference (CCI), also known as crosstalk. Adjacent-channel interference (ACI) Intersymbol interference (ISI)   6. What material can block electromagnetic fields? Typical materials used for electromagnetic shielding include sheet metal, metal screen, and metal foam. Common sheet metals for shielding include copper, brass, nickel, silver, steel, and tin.   7. What blocks electromagnetic interference? Carbons. Carbon materials (e.g., coke, graphite, graphene, carbon fiber, carbon nanofiber and carbon nanotube) are not only conductive electrically, they are good absorbers of electromagnetic radiation over a wide frequency range.   8. Can humans cause electromagnetic interference? The human body functions as an antenna in the low-frequency band used by HBC. Owing to this antenna function, electromagnetic waves radiating from electronic devices or wireless services cause electromagnetic interference (EMI) in HBC devices.   9. What are two sources of electromagnetic interference that can affect data transmission? Electromagnetic interference can be categorized as follows: Narrowband EMI or RFI interference typically emanates from intended transmissions, such as radio and TV stations or mobile phones. Broadband EMI or RFI interference is unintentional radiation from sources such as electric power transmission lines.   10. What is the EMC? Electromagnetic Compatibility, also known as EMC, is the interaction of electrical and electronic equipment with its electromagnetic environment, and with other equipment. All electronic devices have the potential to emit electromagnetic fields. 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 (2017 Korea Electronic Show) From October 17th to 20th, the Korea Electronic Show(KES) will be held in Seoul,Korea. As an exhibitor of the exhibiton, Kynix Semiconductor sincerely invites you to visit this exhibition. It is believed that you can have a better understanding of our company and we can form a stabler partnership.Following are some information about the Korea Electronic Show(KES). OverviewKorea Electronics Show (KES) has always been walking along with the 51 years history of the Korean electronic industry and the most important threshold to the international markets.Having strong connections especially with Asian Pacific IT shows in Japan, Hong Kong, Taiwan, and China, the buyers from North America, Europe, and Middle East tend to schedule every October as an Asian IT show pilgrimage. Exhibit areas:Electronics Parts & Materials; 3D Convergence & 3D Printing; Software & Mobile Apps; IT ConvergenceTheme:Where the Creative Things are!Venue: COEX Hall A, Hall B,World Trade Center Seoul,Seoul, South KoreaScale:1,500 booths representing 500 companies (including 100 overseas)Visitors:70,000(4,000 foreign)Date:October 17(Tue.)-20(Fri.),2017Well-known Exhibitors:UNION SEIMITSU CO., LTD.;SILICONE VALLEY CO., LTD.;SANYO DENKI (THAILAND) CO.,LTD.;MORNSUN.etcGlobal Partners:CEAC, CCPIT, CECC, HQEW(China), TEEMA(Taiwan), JESA, JMA(Japan), HKTDC(Hong Kong), AEECC(Asia Electronics Exhibition Cooperate Conference), Messe Berlin(Germany), CEA(U.S.A), RATEK(Russia), CMAI, TEMA(India), VEIA(Vietnam)Our Booth Number:E450       Floor Plan About Kynix Kynix Semiconductor has founded for 10 years since 2008. These 10 years have witnessed our company's trials of becoming a better and better distributor and supplier in electronic components industry. In 2009, our company established the International Sales Department and became members of TBF and HKInventory. In 2010, we established cooperative relationships with accredited testing organizations like CECCLab, White Horse Lab, AAA...In 2013, we established a strategic partnership with dozens of well-known electronic components manufacturers including TI.In 2015,we reached an electronic components supply strategic partnership with Foxconn.Also ,our B2B trading platform was launched officially,whose members have exceeded 15,000 in 2017. Recently, our partners in electronics field have increased to 700. Our Advantages 1. Strong operation system2. Good warehouse management3. Cooperation with advanced international testing companies4. Cooperation with international high standard logistics companies like UPS, DHL, TNT, FedEx5. Competitive supply from SumSung / Micron / BroadCom / Freescale / Atmel / Cypress and etc...  After-sales ServicesGurantee1.Each product from Kynix has been given a  warranty period of 1 YEAR .During this period , we could provide free technical maintenance if there are any problems about our products.2.If you find quality problems about our products after receiving them , you could test them and apply for unconditional refund if it can be proved.But it's just on this premise that the product is not used and the packing is not damaged . Commitment to QualityKynix has always been laying emphasis on the quality of its products and maintaining a sound cooperative relation with electronic components manufacturers since its founding. It has been conducting quality-monitoring system following the rigid rules in terms of the quality of the product, delivery, and it's after-sales service.   It is claimed by Kynix that all products sold are 100% authentic. Each product has been tested carefully before being sent to the customer. It is our aim to be responsible for our customers and make them satisfactory. ContactIf you have any questions, please contact us through our emails! Hope the exhibition finishes perfectly! We will be there and waiting for your coming!  

A software called DesignDRIVE Fast Current Loop that makes C2000 microcontrollers (MCUs) the first devices to push current-loop performance to less than 1 microsecond, has been introduced by Texas Instruments. Together, TI's C2000 MCU portfolio and DesignDRIVE software delivers System-on-Chip (SOC) functionality which simplifies drive control system development.       The DesignDRIVE Fast Current Loop software out performs traditional microcontroller (MCU)-based current-loop solutions and can simplify designs by eliminating the Field-Programmable Gate Array (FPGA) typically used for external current-loop control. Fast Current Loop software is a free update available for C2000 controlSUITE software.   TI's DesignDRIVE technology is a unified hardware and software platform that makes it easier for engineers to develop and evaluate solutions for a variety of industrial drive and servo topologies. As a key part of DesignDRIVE solutions, the Fast Current Loop software enables developers to achieve higher control performance while saving valuable board space and simplifying thermal considerations.     Features and benefits of TI's DesignDRIVE Fast Current Loop software   · Innovative subcycle Pulse-Width Modulation (PWM) update techniques significantly improve control-loop bandwidths to potentially triple the motor torque response. · A novel cycle-scavenging C2000 MCU needs only 460 nanoseconds for field-oriented control processing. · A new complex controller replaces traditional proportional integration control and facilitates greater stability at higher speeds. · Industrial drive systems designed with Fast Current Loop software on a C2000 MCU, like the TMS320F28379, delivers SOC functionality to reduce board space, complexity and overall cost.      Ref. KY32-TMS320F28379 KY362-C2000    

Overview: The development of lithium-ion batteries as a whole is greatly influenced by their charging systems. The charging technologies, the configuration of the overall charging system, and the charging sequence of electric vehicles are discussed in this article. Evolution of Electric Vehicles The use of electric and hybrid electric vehicles (EVs/HEVs) has grown significantly in recent years, resulting in reduced dependence on fossil fuels and greenhouse gas emissions. This has prompted a wide range of scientific sectors to work on EV/HEV technologies in an effort to replace high-polluting combustion engines. Most research on batteries has been focused on two things: making new chemical compounds to make high-performance batteries and recycling old batteries to avoid big problems with disposal and bad effects on the environment. In engineering equipment, batteries are a frequent source of energy storage. There are many different types of rechargeable batteries with different chemical structures, such as lead acid, nickel cadmium, lithium-ion, etc. These batteries can be chosen based on the design requirements of a storage system, such as capacity, voltage, life, and weight. Rechargeable lithium-ion batteries are used in EVs and HEVs because they have the most power, the highest energy density, and the longest life cycles. This is especially important in light-duty vehicles, where weight is important.  Charging Technologies of Lithium-ion Batteries Lithium-ion batteries are charged optimally with the aid of a battery charger. EV battery chargers are classified as on-board and off-board types based on how fast and how long it takes to charge, as well as when the process starts and ends. On-board chargers are made up of an AC-DC converter for adjusting the voltage and correcting the power factor and a DC-DC converter for regulating the current going into the battery. Because of their size and cost, these chargers only have power levels 1 and 2. Off-board chargers are used to get a high power rate and shorten the time it takes to charge. Fast charging stations use these types of chargers. They have level 3 power and are usually found in public places. A fast charger station is a three-phase grid-connected AC-DC converter. Based on the transformer position for galvanic isolation, there are two common topologies, as shown in Fig. 1. One traditional solution is a big transformer with a line frequency, which makes the charger heavier and less powerful. To solve these problems, a power electronics-based solution is used that uses an isolated DC–DC converter made up of a high-frequency isolated transformer. Most have an active front end (AFE) rectifier that can correct the power factor and an isolated DC-DC converter. A full-bridge DC-DC converter is used to get high power density, efficiency, and reliability. Fig. 1. Fast charger station topologies. Source: IET Power Electronics Most EV control schemes used in fast charge stations are based on the topology of the converter and don't take the chemical structure of the battery into account. But some studies show that charging methods based on electrochemical technologies are more efficient than traditional methods. The constant current–constant voltage (CC–CV) method is one of the most common ways to charge. In CC mode, the battery is charged with a constant current until a certain voltage is reached, at which point the mode changes to CV and stays there until the charge is done. The current drops to a certain value at the end. This method is used most of the time because it is easy to use and cheap. But its performance depends upon the magnitude of the charge current, the time it takes to switch from CC to CV, and the rise in temperature. A high-efficiency charging method that works well can be achieved if these values are properly chosen. System Configuration The power stage and the control unit make up the charger system, as shown in Fig. 2. The power stage has a three-phase AFE rectifier, a full-bridge DC-DC converter, a low-pass filter, and a battery. The control unit has a detect phase unit, an FDA, a current controller, and a modulator unit. A full bridge DC-DC converter is reliable and can control many things at once. This converter is used to charge batteries. It has an H-bridge inverter, a high-frequency transformer, and full-bridge diodes.  Fig. 2. Overall charge system configuration. Source: IET Power Electronics The switching method of a DC-DC converter is based on phase-shifting pulse width modulation. The amplitude of the output voltage is changed by changing the angle between the complementary pulses of the switches. The control unit is made up of four smaller parts: phase difference detection, frequency detection algorithm (FDA), controller, and modulator. By injecting a sinusoidal ripple current with a specific frequency, the phase difference between the current and voltage can be found. Then, the perturb and observe (P and O) algorithm is used to find the FDA unit's optimal frequency, which has the least phase difference. The next step is for the current control unit to make a control signal, which is the duty cycle of the DC-DC converter. In the last step, the modulator uses the control signal to make the right switching pulse. Sinusoidal Ripple Charging Scheme (SRC) A separator and two electrodes make up a Li-ion rechargeable battery, as indicated by the electrochemical model in Fig. 3. Li+ ions are transferred from the cathode to the anode during the charging process. Conventional battery charging schemes, like CV and CC-CV, have problems, such as taking a long time to charge. In the SRC method, an AC current with a DC offset current is used to charge the battery.  Fig. 3. Lithium-ion battery charging process. Source: IET Power Electronics Accordingly, it can cut down on the time it takes to charge a battery by figuring out the optimal ripple current frequency and making sure that the battery's ac impedance is as low as possible. The battery's dynamic model's impedance spectrum backs up this assumption. Compared to the SRC charging method, the square pulse charging method, which is a type of AC ripple current charging, is less efficient, causes the temperature to rise faster, and takes longer to charge.  Summarizing with Key Points: Some of the takeaways from the article are as follows: Rechargeable lithium-ion batteries are used in electric and hybrid electric vehicles because of their high power, high energy density, and prolonged life cycles.Electric vehicle battery chargers are categorized as on-board and off-board, depending on how quickly and how long it takes to charge a battery, as well as when the process begins and ends.On-board chargers only have up to 1 and 2 power levels and are composed of an AC-DC converter and a DC-DC converter. An off-board charger that has a three phase grid-connected AC-DC converter is the fast charging station. They are typically installed in public areas and have level 3 power.An isolated DC–DC converter constructed of an isolated high-frequency transformer solves these concerns with traditional chargers. Full-bridge DC-DC converters provide excellent power density, efficiency, and reliability.The CC–CV charging method is popular because it's cheap and straightforward to use. However, its performance depends on the charge current, time to switch from CC to CV, and temperature rise. The power stage and the control unit make up the charger system. The power stage has a three-phase AFE rectifier, a full-bridge DC-DC converter, a low-pass filter, and a battery. The control unit has a detect phase unit, an FDA, a current controller, and a modulator unit.The control unit has four smaller parts: phase difference detection, frequency detection algorithm, controller, and modulator. The phase difference between the current and voltage can be found by injecting a sinusoidal ripple current with a certain frequency. This blog post is part of a full research article from IET Power Electronics. The featured image is used courtesy of OPEN AI.

Imec, the world-leading research and innovation hub in nanoelectronics and digital technology, announced today at the 2017 Symposia on VLSI Technology and Circuits the world's first demonstration of a vertically stacked ferroelectric Al doped HfO2 device for NAND applications. Using a new material and a novel architecture, imec has created a non-volatile memory concept with attractive characteristics for power consumption, switching speed, scalability and retention. The achievement shows that ferro-electric memory is a highly promising technology at various points in the memory hierarchy, and as a new technology for storage class memory. Imec will further develop the concept in collaboration with the world's leading producers of memory ICs.  Ferro-electric materials consist of crystals that exhibit spontaneous polarization; they can be in one of two states, which can be reversed with a suitable electric field. This non-volatile characteristic resembles ferromagnetism, after which they have been named. Discovered more than five decades ago, ferro-electric memory has always been considered ideal, due to its very low power needs, non-volatile character and high switching speed. However, issues with the complex materials, the breakdown of the interfacial layer and bad retention characteristics have presented significant challenges. The recent discovery of a ferro-electric phase in HfO2, a well-known and less complex material, has triggered a renewed interest in this memory concept."With HfO2, there is now a material with which we can process ferro-electric memories that are fully CMOS compatible. This allows us to make a ferro-electric FET (FeFET) in both planar and vertical varieties," noted Jan Van Houdt, imec's chief scientist for memory technology. "We are working to overcome some of the remaining issues, such as retention, precise doping techniques and interface properties, in order to stabilize the ferro-electric phase. We are now confident that our FeFET concept has all the required characteristics. It is, in fact, suitable for both stand-alone and embedded memories at various points in the memory hierarchy, going all the way from non-volatile DRAM to Flash-like memories. It has particularly interesting characteristics for future storage-class memory, which will help overcome the current bottleneck caused by the differences in speed between fast processors and slower mass memory."Imec recently presented the first, extremely positive results to its partners. The research center is now offering further development and industrialization of the vertical FeFET as a program to all its memory partners, which include the world's major companies producing memory ICs."FeFETs can be used as a technology to build memory very similar to Flash-memory, but with additional advantages for further scaling, simplified processing, and power consumption," added Van Houdt. "With our longstanding R&D and processing experience on advanced Flash, we are uniquely positioned to offer our partners a head start in this exciting opportunity. They can then decide how best to fit ferro-electric memories in their products and chips." Ref:KY32-K9T1G08U0M-YIBOKY32-CY7C1357S-100AXCKY32-AT49BV162AT(T)  

 If you disassemble several electronic devices, you will discover a printed circuit board (PCB), which is a small green board with maze-like markings.So what is a PCB? These small green boards aid in the operation of electronic devices. The device would not function without them. PCBs connect all of the other components inside, allowing you to use your electronic device for its intended purpose.Despite its small size, the PCB manufacturing process is quite extensive. Whether you make your own or use a PCB manufacturer, multiple steps are required for the board's development. Because each step is critical to the overall process, let's take a closer look at the 4-layer PCB production flow. The production flow of a 4-layer PCB Catalog I Parts of printed circuit boards1.1 Features of printed circuit boards1.2 The role of printed circuit boardII PCB manufacturing processFAQ I Parts of printed circuit boards To have a thorough understanding of Printed Circuit Boards (PCBs), it is important to know the various parts that are used to make the boards.The most obvious starting point is the board itself. It is plastic, reinforced with glass. The next most obvious parts are the lines and pads that connect together. These are made of copper, and are known as ‘traces’. They conduct electricity, allowing electrical charges to be carried through the board. They are similar to wires, but are much finer, and are used to carry the electricity to the end-point (one of the various types of components within the board).  Figure 1. Essential parts of a printed circuit board Simple PCBs are single-sided, with one copper layer. These are structured with one side having all the components, while the other side had the traces. Holes are placed through the board for the circuit to be carried from the trace to the component. For many years, all boards were made in a single-sided design. By definition, double sided PCBs have traces on both sides of the board.To allow the boards to be more complex and control additional functions, multi-layer boards are used. Additional layers of board have their own set of traces and components. In developing multi-layer boards, a range of issues needed to be addressed. Firstly, it is essential that the copper connections do not cross each other, as this would compromise the path of the electrical circuit. Other factors that need to be considered are resonance and noise and capacitance.The layer set in place above the copper is called the soldermask. This is a form of insulation, ensuring that the copper traces aren’t affected by any metal that may come into contact with it. It is traditionally colored green. It is designed to have gaps that expose the copper in specific places, providing points where components can be soldered to the board. The silkscreen is a layer that is printed onto the soldermask. It is a layer where text can be printed (letters and numbers) that provide instructions for the user.A range of components can be incorporated into a PCB. Without components, the PCB is simply a conductor of electricity, with no function. Components can be grouped into two broad categories – passive (components that do not require direction) and active (components that only function when they receive current from one direction). Common components include:1. Batteries: these provide the circuit with voltage.2. Capacitators: The store electricity for later use. They are available as polarized or non-polarized.3. Diodes: allows current to pass in one direction only, blocking the other.4. Inductor: These coils store charge in a magnetic field.5. Light emitting diodes (LEDs). These light up when current flows is applied. They only allow current to flow in one direction.6. Resistors: These control the electric current as it passes through. The level of resistance provided varies based on the needs of the engineer. 7. They are made in different color codes to show the level of resistance.8. Switches: These can be open or closed, allowingor blocking current.9. Transistors: These are a form of switch that performs changes function based on the voltage passing through.10. Vias: small holes in the board that allow a signal to be passed from one side to the other 1.1 Features of printed circuit boards1. After the electronic component is encapsulated, the electrical conduction can be realized.2. It is required that there should be no current flow in the insulating part.　3. It is required that there must be current flow in the conduction part.　4. As the mechanical support for the fixation and assembly of components, it must meet the requirements of mounting components.5. There must be complete and clear recognition characters and component symbols.6. It can be fixed to the appropriate part of the machine. 1.2 The role of printed circuit boardAfter the printed circuit board is adopted in the electronic equipment, the error of manual wiring is avoided because of the consistency of the same kind of printed circuit board. And the automatic insertion or mounting, automatic soldering and automatic detection of electronic components can be realized. In a word, it ensures the quality of electronic equipment, improves the labor productivity, reduces the cost, and is convenient for maintenance.Figure 2. Printed circuit board II PCB manufacturing process Now, let's take four layers as an example to see how printed circuit boards are made.  Figure 3. Chemical clean Step 1: In order to obtain an etching pattern with good quality, it is necessary to make sure that the corrosion resistance layer is firmly combined with the substrate surface, and the substrate surface is required to be free of oxidation layer, oil pollution, dust, fingerprint and other dirt. Therefore, before coating the corrosion resistant layer, it is necessary to clean the surface of the board and make the surface of the copper foil reach a certain degree of coarsening. Core material: when you start making four layers, the inner layer (the second and the third layer) must be done first. The core material is a copper sheet composed of glass fiber and epoxy resin on the upper and lower surfaces.   Figure 4. Cut sheet →dry film lamination Step 2: In order to make the shape we need on the core material, we first paste a dry film (photoresist) on the core material. The dry film is composed of polyester film, photoinduced corrosion resistant film and polyethylene protective film. When sticking the film, the polyethylene protective film is stripped from the dry film, and then the dry film is pasted on the copper surface under the condition of heating and pressurization.  Figure 5.  Image expose→image develop Step 3: Under the irradiation of ultraviolet light, the photoinitiator absorbs the luminous energy to decompose into free groups, which in turn initiate the polymerization and crosslinking of photopolymerizable monomer. After the reaction, a high molecular structure insoluble in dilute alkali solution is formed. The polymerization reaction will continue for a period of time. In order to ensure the stability of the process, the polyester film should not be torn off immediately after exposure. It should stay for more than 15 minutes, so that the polymerization reaction can continue and the polyester film should be torn off before development. Image Develop: the active group in the unexposed part of the photosensitive film reacts with dilute alkali solution to produce a soluble substance and then it dissolves, leaving a graphic part that has been photosensitive crosslinked and solidified.  Figure 6.  Copper etch Step 4: In the production of flexible printed circuit board or printed circuit board, the copper foil is removed by chemical reaction to form the required loop pattern. The copper beneath the photoresist is preserved from etching.   Figure 7. Strip resist→post etch punch→AOI inspection→oxide Step 5: The purpose of removing the film is to remove the corrosion resistant layer retained on the surface of the etched board so that the copper foil below can be exposed. "Membrane slag" filtration and waste liquid recovery should be properly treated. If the water washing after the film removing can completely cleans the board, you can consider not doing pickling. Finally, the board should be completely dry after cleaning.   Figure 8. Lay-up with prepreg Step 6: Before entering the press machine, it is necessary to prepare the raw materials for each multilayer board for lay-up operation. In addition to the oxidized inner layer, the prepreg is also needed. The function of the lamination is to stack the boards covered with protective film in a certain order and place them between the two-layers of steel plate.  Figure 9.  Lay up with copper foil→vacuum lamination press  Step 7: Cover the current core material with a layer of copper foil on both sides, and then cool to room temperature after multi-layer pressurization, which requires temperature and pressure to be measured over a fixed period of time. And a multilayer sheet is finished.   Figure 10.  CNC drill Step 8: Under the accurate condition of inner layer, the CNC drilling machine drills according to the mode. Drilling accuracy is required to ensure that the hole is in the correct position.    Figure 11. Electroless copper Step 9: In order for the through hole to be conductive between the layers ,which means the resin and glass fiber bundles of the non-conductor part of the hole wall should be metalized), copper must be filled in the hole. The first step is to coat the hole with a thin layer of copper, which is a complete chemical reaction. The final copper plating is 1/1000000 of 50 inches thick.   Figure 12. Cut sheet→dry film lamination Step 10: Photoresist: this time we apply photoresist to the outer layer.   Figure 13. Image expose→image develop Step 11:This time we finish the outer exposure and development.   Figure 14. Copper pattern electro plating Step 12:This also becomes the secondary copper plating, the main purpose is to thicken the line copper and the through-hole copper.  Step 13:Its main purpose is to prevent etching and to protect the copper conductors covered by it from attacking during alkaline copper etching. The copper conductors include all the copper lines and the through holes interior.   Figure 15. Strip resist Step 14:We already know the purpose. All we have to do is to make the copper on the surface exposed by using chemical methods.   Figure 16.  Copper etch Step 15:We also know the purpose of etching. And the tinned part protects the copper foil below.   Figure 17. Tack dry→image expose→image develop→thermal cure solder mask Step 16:The welding resistance layer is used to expose the welding pad, that is, the green oil layer, which is actually digging holes in the green oil layer and exposing the welding pad and other places that do not need to be covered with green oil. Suitable surface features can be obtained by proper cleaning.  Figure 18. Surface finish Step 17:The process of hot air leveling solder coating (commonly known as tin spray) is to soak the printed circuit board with flux, then dip it in the molten solder. Next, pass it between the two wind knives and blow off the excess solder on the printed board with the hot compressed air in the wind knives. At the same time, the excess solder in the metal hole is eliminated, so as to obtain a bright, smooth and uniform solder coating.Gold finger (Gold Finger, or Edge Connector) is designed to use the connector insertion as an outlet for external contact with the board, so the gold finger process is required. Gold was chosen because of its superior conductivity and oxidation resistance. But because of the high cost of gold, it can only be used for gold fingers, local plating or electroless gold. FAQ 1. What is a PCB in a printer?While design of a printed circuit board (PCB) can be done internally, manufacturing is generally outsourced. This dependence often results in uncontrollable, and unexpected delays. ... It is here that desktop PCB printers are aiming to come to the rescue. 2. How much does it cost to print a PCB?In general, the cost to produce a PCB will cost between $10 and $50 per board. 3. How does a PCB printer work?A special printer called a plotted printer is used to print the design of the PCB. It produces a film that shows the details and layers of the board. When printed, there will be two ink colors used on the inside layer of the board: Clear Ink to show the non-conductive areas. 4.Why are PCB green?It is due to the solder mask, which protects the copper circuits printed on the fibre glass core to prevent short circuits, soldering errors, etc. ... The colour of the solder mask gives the board its appearance. 5. How much does custom PCB cost?At BatchPCB, a two-layer board costs $2.50 per square inch (about $0.40 per square centimeter), while a four-layer board costs $8 for the same area (about $1.24/cm2). The first step in creating a custom PCB is laying out the schematic view. 6. How do I print directly from PCB?A laser printer is used to print an image of the PCB on special “transfer paper” which is then placed on the bare copperclad board and either ironed or run through a modified laminator to transfer the image to the copper. 7. What does PCB stand for?printed circuit board. A printed circuit board, or PC board, or PCB, is a non-conductive material with conductive lines printed or etched. Electronic components are mounted on the board and the traces connect the components together to form a working circuit or assembly. 8. What is PCB made of?copper circuitry. Printed circuit boards (PCBs) are usually a flat laminated composite made from non-conductive substrate materials with layers of copper circuitry buried internally or on the external surfaces. They can be as simple as one or two layers of copper, or in high density applications they can have fifty layers or more. 9. Which type of PCB is more economical type?Aluminum-Backed PCBs. Aluminum is inexpensive, making almost 8.23% of planet's weight, and leads to most economical manufacturing process. PCBs made up of aluminum are easily recyclable and non-toxic in nature, making them as ideal source for energy conservation. 10. How do you choose a PCB material?Electrical functionality is based on PCB function, which makes it a good criterion for design-based circuit board material selection. According to function, PCBs may be classified as the following board types: High Frequency (High Speed) – These boards can accommodate frequencies in the 500MHz – 2GHz range.