The Kynix Blog

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.

IntroductionⅠ Operating Principle of Fuel Pump Relay1.1 How does the Fuel Pump Relay Work?1.2Working Principle of Vehicle Electric Fuel PumpⅡ Fuel Pump Relay Testing and ReplacementⅢ Fuel Pump Relay Inspection and Maintenance Structure FlowⅣ Detection Methods for Faults without Fault Memory of Fuel Pump RelayⅤ Inspecting the Fuel Pump Relay UnitⅥ What Causes Fuel Pump Relays to Fail?Ⅶ How to Prevent Fuel Pump Relay from Getting Damaged after Replacement?Ⅷ How to Diagnose a Bad Fuel Pump Relay?Ⅸ FAQIntroductionWhat is the fuel pump relay? How does it work? There are some measures to deal with the failure of fuel pump relay. Just keep reading our guide to find out!Ⅰ Operating Principle of Fuel Pump RelayWhen the engine starts, the fuel pump relay turns off. The oil pressure sending unit supplies power to the fuel pump at this point. When you turn off the ignition, the fuel pump relay is re-engaged for a short period, allowing the fuel pump to power down and shut off.Figure 1 Operating principle 1.1 How does the Fuel Pump Relay Work?A fuel pump relay functions similarly to a light switch in your home, turning on the lights.The main difference is that there is no direct contact with the switch; rather, the switch is triggered when a sufficient amount of electricity accumulates.The fuel pump is in charge of regulating the pressure within the engine to ensure proper operation.When the engine requires fuel, the pressure is increased to start the injection of fuel into the engine.If there was insufficient pressure, the engine would not receive the necessary fuel, which could result in a misfire.The difference is that instead of directly turning on the internal switch, the control circuit is turned on. This coil then generates an electromagnetic field, closing a pair of metal contacts within the relay. The metal contacts are linked to a controlled circuit, which ultimately activates the fuel pump.1.2 Working Principle of Vehicle Electric Fuel PumpThe electric fuel pump assembly is installed and immersed in fuel in the fuel tank. It is controlled by the ECM and sucks fuel from the fuel tank, filters, and regulates pressure before delivering it to the fuel manifold.The electric fuel pump assembly consists of a fuel pump, a fuel filter, an engine oil pressure regulator, and an oil level sensor.A DC motor, a vane pump, and an end cover comprise the electric fuel pump (integrated check valve, pressure relief valve, and anti-electromagnetic interference components).Figure 2 The wiring diagram of the electric fuel pumpWhen the ignition switch is turned on, the main relay is activated to provide 12V power to the fuel pump relay. At this point, the fuel pump relay will be activated for approximately 2 seconds, causing the electric fuel pump to operate for 2 seconds. Raise the oil pressure in the fuel main pipe to a safe level before starting the engine.When you turn off the engine, the electric fuel pump shuts down. At this point, the one-way valve is closed to maintain residual pressure in the fuel line, making it easier to restart the engine. When the oil pressure on the oil outlet side becomes excessively high, the safety valve opens to drain the fuel, preventing the fuel pressure from becoming excessively high.Figure 3 Electric fuel pumpThe vehicle's current electric fuel system is a non-return system. An oil pressure regulator integrated with the fuel pump assembly adjusts the fuel system pressure to around 380kPa. The fuel that has passed through the fuel filter is redirected to the oil pressure regulator. If the oil pressure is too high, open the regulator's oil return valve to drain the oil and stabilize the oil pressure to a certain value. To detect the fuel level, an oil level sensor is installed in the fuel pump assembly. The sliding resistance principle is used by the oil level sensor. When the oil level drops, the float floating on the oil surface moves downward, causing the contact of the sliding resistance to move downward, and the sensor's resistance value to rise. The oil level sensor has a resistance range of 3108. (depending on the car models).Ⅱ Fuel Pump Relay Testing and Replacementvideo: How to test and replace a fuel pump relayHow to test fuel pump relay? You will learn from this video. In the same time, the principles shown here apply to most vehicles.Ⅲ Fuel Pump Relay Inspection and Maintenance Structure FlowDetection methods for faults without fault memory of Fuel pump relay1. Fuel pump relay fault detection and maintenance schemeThe fault memory of engine control unit is read by detector. Short circuit of fuel pump control to positive pole, short circuit of fuel pump control to ground and open circuit of fuel pump control are three common fault memories related to fuel pump relays.For the above three fault modes, the following detection and maintenance methods are formulated respectively:2. Fuel pump control for positive pole short circuit repair method.First, disconnect the fuel pump relay plug and measure the voltage between the relay slot 2 pins and grounding when the ignition switch is turned on. The rated value should be between -1V and 1V; if the measured value is not within this range, a short-circuit to the positive pole of the connecting 2-pin excitation line exists. If the measured value falls within the above-mentioned rated range, there is no short-circuit to the positive pole. Then, look for any disconnection. Turn off the ignition switch first, then unplug the engine ECU plug, and measure the resistance between pin 2 of the relay slot and pin 80 of the engine ECU plug (for the new Jetta model, the engine ECU controls the fuel pump relay ground terminal through pin 80). If the resistance exceeds 30, the circuit is open. If the resistance is less than 30, the circuit from the fuel pump relay to the engine ECU is satisfactory. Based on the above findings, the fault can only be found in the relay itself, and the relay should be replaced.3. Method for repairing a fuel pump control to a ground short circuit faultTurn off the ignition, disconnect the fuel pump relay, and measure the resistance between relay slot pin 2 and the engine ground point. If the resistance value is less than 9MQ, the excitation line has been short-circuited to the ground. If the resistance value is greater than 9MQ, the line is in good condition. The short-circuit point must be located within the relay, and the relay must be replaced.4. Fuel pump control open-circuit fault repair methodCheck to see if the appropriate fuses and fuel pump relays are properly installed, dirty, or broken. When no fault is found, remove the fuel pump relay and measure the voltage between pins 1 and 3 of the fuel pump, as well as the engine grounding (i.e. check the power supply of the relay). If the measured voltage is less than 11.5V, it means that the wire connecting the detection point to the battery is broken. If the measured voltage is greater than 11.5V, the voltage supply is functioning normally. The relay actuator and fuel pump should then be checked. If the fuel pump still does not work, the fault is not with the relay. It should keep checking the line between the relay and the fuel pump. If the problem persists after removing the line fault, the fault can only be in the fuel pump, which should be replaced: If the fuel pump is powered on after bridging 1 and 5 Pins, the fault is limited to the active part of the relay and the relay itself, and the detection method is the same as 1" Maintenance method of fuel pump control for Positive pole Short-circuit Fault ".Ⅳ Detection Methods for Faults without Fault Memory of Fuel Pump RelayWhen the detector is used to diagnose the fuel pump executive components, the following three execution results will be obtained. We will examine the three different execution results item by item:1. The fuel pump is turned on and running.In the absence of a fault code, the correct activation of the fuel pump indicates that the system is fault-free.2. When the fuel pump relayis activated, the action of the fuel pump's non-reactive relay indicates that the excitation line is normal. The relay, the positive power supply, and the fuel pump are the three components that must be tested. Pull out the fuel pump relay, measure its slot 1 foot and 3 feet to engine ground between voltage (i.e., check the relay power supply): if the measured voltage is less than 11.5 v, the related testing point between thebattery wire break, if the voltage is greater than 11.5 v, the voltage supply is normal. Checked the oil pump parts, using the transfer line bridge slot on the 1,5 foot: if the fuel pump still does not work, the fault is not in the relay, should continue to check the path of the relay to the fuel pump, still did not solve the problem, after exclusion of line fault, fault can only be in the fuel pump, fuel pump needs to be replaced, if the bridge after 1, 5-foot pump electricity work, illustrates the fault in the relay, the fuel pump relay must be replaced.3. The relays for the fuel pump and the fuel pump are not working, necessitating a thorough inspection of all relevant parts. Check to see if the appropriate fuses and fuel pump relays are properly installed, dirty, or broken. Remove the engine ECU and short-circuit the terminal connecting the engine ECU plug to the fuel pump relay excitation line (pin 2) to ground if no fault is found (for the new Jetta, the corresponding terminal number is 80). If the fuel pump is running at this time (the relay must act), the system from the relay to the fuel pump is functioning normally, and the fault may be in the engine ECU. The phenomenon is the same if the fuel pump is not running and only the relay is activated "The fuel pump relay is turned on.  If both the relay and the fuel pump are not operational, the relay will not function normally even if the engine ECU sends the grounding excitation signal. At this point, the power supply, executive, and excitation parts of the relay must be checked one by one.The method described above for detecting a fuel pump relay can also be used as a guide for detecting other relays. We need to conduct specific analyses for different models during the actual maintenance process.Ⅴ Inspecting the Fuel Pump Relay UnitWhen you open the unit, the first thing you should do is a smell for a faint burnt odor. This would indicate whether or not the temperature has risen too high in there.Next, look for burn marks that indicate an excessive level of resistance. They're usually found near the offending connections or components on the circuit board.Then, place your thumb on the large relay on the circuit board and wiggle it. If the big part of the relay wiggles at all (not the small hinged part), the solder joints are bad and must be re-soldered.Figure 4 bad-solder-jointsExamine the contact points between the relay's hinged and stationary parts. It's difficult to say how much pitting or discoloration is normal, but all of the ones I've seen (including the perfectly good ones) have some pitting. If they're really bad, sanding them may be able to extend their life, but it's impossible to say how much.Check that all of the solder joints on the solder side of the circuit board are smooth and shiny. Poor soldering is indicated by a dull or crinkly appearance.Ⅵ What Causes Fuel Pump Relays to Fail?A fuel pump relay failure can occur for a variety of reasons, including:1The relayshave windings that can be burned due to high voltage short circuits.2A faulty relay is caused by a faulty coil or faulty connections.3Any unfavorable situation, from environmental dust to a sudden voltage increase, can harm the fuel pump relay.4Failure of the relay may occur due to the breaking of inner terminals, corrosion around the electrical contacts, breaking of coil wires, and other factors.5Overheating of the relay may cause it to melt. A burned relay may also cause a meltdown in the fuse panel. It is frequently difficult to remove, and as a result, the entire fuse box must be replaced.l?6When there are a lot of electrical failures, the fuel pump usually wears out at the same rate.7Before you replace the relay, you must first identify and resolve the issue that caused it to fail.8The electric fuel is powered solely by the engine, not by the fuel pump relay. By remaining submerged in the fuel, the relay only keeps the fuel temperature cool.9Keep your fuel tank full at all times to avoid shortening the life of your fuel pump relays.10When you turn off your vehicle's engine with a low fuel level, the engine can drain from the priming chamber into the fuel delivery system.11Without enough fuel, thefuel pumpwill run hot and unprimed, potentially damaging the pump motor. As a result, when the tank is full of gas, a fuel pump relay turns off.12The engine should not be started if the fuel pump relay is still hot.13Parking one's car on the front porch in the sun is a common blunder. It heats the engine, causing the fuel pump relay to backfire. Finally, it takes time for the vehicle to start and for the fuel to cool.14The relays have a winding that is frequently burned due to the high voltage. When the relays burn out or become damaged, they must be replaced.15Because the fuel pump relay controls the fuel pump, any fault with the relay can cause problems with the pump, causing the vehicle to drive incorrectly.Ⅶ How to Prevent Fuel Pump Relay from Getting Damaged after Replacement?Overloading of relays. Every relay has a maximum capacity, and exceeding that capacity may cause the contacts to fail.Figure 5 Fuel pump relay replacementHigh discharged currents may flow from power supplies with capacitors in their outputs. This heats and melts the contacts. Current limiters solve the majority of these issues, but they do not control capacitive discharge effects. They may also take some time to respond because the limiters use a feedback loop as part of the power supply control system.Digital I/O cards such as models 40-411, 40-412, and 40-413 can help to reduce the occurrence of welds caused by faulty test targets.Frequently, an excellent high-quality relay solves the majority of the problems.Keeping the relay clean is also good preventative maintenance. Allow the relay to dry after gently rubbing it with ethanol.Ⅷ How to Diagnose a Bad Fuel Pump Relay?Typically, car problems are caused by faulty fuel pump relays. A faulty relay is the result of a faulty coil or connection. To determine the cause of the bad relay, pull it out of the socket.Figure 6 How to tell if fuel pump relay is badConsult a service manual to locate your fuel pump relay. Before beginning, this task, learn more about how a multimeter or ohmmeter works.Check the Coilstep 1: Set up the multimeter to read the ohms. The ohm scale resembles a horseshoe in shape.Step 2: To test the multimeter, touch the meter leads together. You should get a reading of zero ohms.When the test leads across the relay's coil are touched, they should read around 70 ohms. Assume the meter reads zero or infinite ohms. In that case, the coil is either shorted or open at the same time, and your relay is faulty.Examine the ContactsStep 1: Connect the test leads from one side of the relay coil to the chassis ground.Step 2: Connect the other test lead to the vehicle's battery. The relay should be turned on, and you should hear or feel a click.      5. Connect the multimeter to the relay's COMMON and NORMALLY OPEN contacts, and the relay should read zero. If this does not occur, the contacts are not connected because the relay is faulty.                 6. Exercise caution when connecting your test leads to the battery. If the battery positive is too close to the ground connection, a spark can occur.      7. You will require the following items:Your relay's diagramMultimeterTwo alligator clips on both ends of two electronic test leadsⅨ FAQ1. What could result in a misfire?The engine would not receive the necessary fuel.2. What is responsible for regulating the pressure within the engine?The fuel pump.3. How much power does the main relay provide to the fuel pump relay?12V4. How does the electric fuel pump operate when the ignition switch is turned on?Raise the oil pressure in the fuel main pipe to a safe level before starting the engine5. What happens when the oil pressure on the oil outlet side becomes excessively high?The safety valve opens to drain the fuel6. Where are burn marks usually found?Near the offending connections or components on the circuit board.7. What is the first thing you should do when you open the Fuel Pump Relay Unit?Place your thumb on the large relay on the circuit board and wiggle it8. What can high discharged currents flow from power supplies with?Capacitors9. What solves the majority of the problems?An excellent high-quality relay 10. What do you need to know about a bad fuel pump relay?How a multimeter or ohmmeter works.11. What do you need to do to diagnose a bad fuel pump relay?Set up the multimeter to read the ohms12. What is the reading of a bad fuel pump relay?Zero ohms.

Introduction Everyone has heard of FPGA more or less, such as Bitcoin mining, or Microsoft said before that it will use FPGA instead of CPU in the data center. So what exactly is it? Why use it? Compared with CPU, GPU, and ASIC, what are the characteristics of FPGA? FPGA is a chip that can reconfigure circuits and is a hardware reconfigurable architecture. Through programming, users can change its application scenarios at any time, and it can simulate various parallel operations of hardware such as CPU and GPU. By interconnecting with the high-speed interface of the target hardware, the FPGA can complete the low-efficiency part of the target hardware, thereby achieving acceleration at the system level. What Is an FPGA? Catalog Introduction Ⅰ FPGA vs CPU vs GPU vs ASIC Ⅱ Five Advantages of FPGA 2.1 Performance 2.2 Time-to-Market 2.3 Cost 2.4 Stability 2.5 Long-Term Maintenance Ⅲ New Applications of FPGA Ⅳ Development Trend of FPGA Ⅴ FAQ Ⅰ FPGA vs CPU vs GPU vs ASIC The core difference between FPGA and CPU, GPU, ASIC chips, etc. is that the connection and logic layout of the underlying operation unit are not solidified. Users can program the logic unit and switch array through EDA software to configure the function, so as to realize the integration of specific functions.FPGA appears as a semi-custom circuit in the field of application-specific integrated circuits (ASIC), which not only solves the shortcomings of custom circuits, but also improves the limited number of original programmable device gate circuits. Compared with ASIC chips, an important feature of FPGA is its programmable characteristics, that is, the user can specify the FPGA to realize a specific digital circuit through the program. Furthermore, FPGA chips are one of the best choices for small batch systems to improve system integration and reliability. Figure 1. FPGA Basic Structure So why is FPGA so fast? This is all because the computer's CPU(central processing unit) and GPU(graphics processing unit) belong to the von Neumann structure, with instruction decoding and execution, and shared memory. FPGAs, on the other hand, are instruction-free and memory-free architectures that make FPGA chips much more energy-efficient than CPUs or even GPUs. Figure 2. Von Neumann Structure In the von Neumann architecture, since the execution unit (such as the CPU core) may execute any instruction, so an instruction memory, a decoder, an operator of various instructions, and branch and jump processing logic are required. Due to the complex control logic of the instruction stream, it is impossible to have too many independent instruction streams. Therefore, the GPU uses SIMD (single instruction, multiple data) to allow multiple execution units to process different data at the same pace, and the CPU also supports SIMD instruction. The function of each logic unit of the FPGA has been determined during reprogramming, and no instructions are required. Figure 3. Computer CPU If the GPU is used for acceleration, in order to fully utilize the GPU computing, the batch size cannot be too small, and the delay will be on the order of milliseconds. Using FPGA to accelerate, only microsecond-level PCle delay is required. Why is FPGA so much lower latency than GPU? This is basically an architectural difference. FPGAs have both pipeline parallelism and data parallelism, while GPUs have almost only data parallelism (with limited pipeline depth).For example, FPGA chips can change the running hardware design on the chip every few seconds, while chips such as CPU and ASIC are already solidified when they leave the factory and cannot be changed. If ASIC, CPU, GPU, etc. are built buildings, and the routes of rooms, corridors, and stairs in the building have been fixed, while the interior of FPGA is similar to the magic staircase in Hogwarts, which can change the route of room to room at any time. In addition, FPGA does not need to compile the instruction system at the software application level like CPU and GPU. To program FPGA, use hardware description language, and directly compile and burn it into a combination of transistor circuits, that is, directly use transistor circuits to implement user algorithms.The biggest feature of FPGA is its flexibility. It can realize any digital circuit you want and can customize various circuits. Reduce the shackles of special chips, truly tailor-made for your own products, you can flexibly change the design during the design process, and have field programmability, so it is especially suitable for applications that require continuous changes in physical operation logic, such as AI algorithm optimization, data center applications, etc. Architecture Throughput（int ops） Delay Flexibility CPU ~1T N/A Very High GPU ~10T ~1ms High FPGA(Stratix V) ~1T ~1us High FPGA(Stratix 10) ~10T ~1us High ASIC ~10T ~1us Low The FPGA is set up by the RAM stored on the chip to reset its working state, so the on-chip RAM needs to be programmed when working. Users can use different programming methods according to different configuration modes, which can be said to be very flexible and convenient. The FPGA has the following configuration modes:🔺Parallel Mode: Parallel PROM, Flash configures FPGA.🔺Master-Slave Mode: One PROM configures multiple FPGAs.🔺Serial Mode: Serial PROM configures FPGA.🔺Peripheral Mode: The FPGA is used as a peripheral of the microprocessor and programmed by the microprocessor. Computational performance compared with CPU: For example, Stratix series FPGAs perform integer multiplication operations, and their performance is equivalent to that of a 20-core CPU, and for floating-point multiplication operations, their performance is equivalent to an 8-core CPU.Computational performance compared with GPU: FPGA performs integer multiplication and floating-point multiplication operations. There is an order of magnitude difference in performance compared to GPU. The computing performance of GPU can be approached by configuring multipliers and floating-point operation components. Figure 4. CPU and GPU Architecture Diagram The core advantage of FPGA for performing computation-intensive tasks: tasks such as search engine sorting and image processing have strict requirements on the return time limit of results, and it is necessary to reduce the delay of computing steps. Under the traditional GPU acceleration scheme, the data packet size is large, and the delay can reach the millisecond level. Under the FPGA acceleration scheme, the PCIe latency can be reduced to the microsecond level. Driven by long-term technology, the data transmission delay between CPU and FPGA can be reduced to less than 100 nanoseconds.The FPGA can build the same number of pipelines (pipeline parallel structure) for the number of data packet steps, and the data packets can be output immediately after being processed by multiple pipelines. The GPU data parallel mode relies on different data units to process different data packets, and the data units need to be input and output consistently. For stream computing tasks, the FPGA pipeline parallel structure has a natural advantage in latency. FPGA is used to process communication-intensive tasks and is not limited by network cards. It outperforms CPU solutions in terms of packet throughput and delay, and has strong delay stability. Therefore, FPGAs have obvious advantages over CPUs when performing large data processing tasks with high repetition rates.By programming the FPGA, the user can change the internal connection structure of the chip at any time to realize any logic function. Especially in industries with immature technical standards or rapid development and change, FPGA can effectively help enterprises reduce investment risks and sunk costs, and is a functional and economical choice. Figure 5. Computer GPU With the evolution of intelligent market demand, highly customized chips (ASIC SoC) have led to a sharp increase in market risks due to the large scale of non-repetitive investment and long R&D cycle. Relatively speaking, FPGA has advantages in the field of parallel computing tasks, and can replace some ASICs in the field of high performance and multi-channel. The demand for multi-channel computing tasks in the field of artificial intelligence (AI) drives the evolution of FPGA technology to the mainstream. Figure 6. ASIC SoC Ⅱ Five Advantages of FPGA 2.1 Performance Taking advantage of hardware parallelism, FPGAs break the sequential execution model and complete more processing tasks per clock cycle, surpassing the computing power of digital signal processors (DSPs). BDTI(Big Data Test Infrastructure), a well-known analysis and benchmarking company, has published benchmarks that show that in some applications, FPGAs can handle many times more processing power per dollar than DSP solutions. Controlling input and output (I/O) at the hardware level provides faster response times and specialized functionality to meet application needs. 2.2 Time-to-Market Despite increasing time-to-market constraints, FPGA technology offers flexibility and the ability to rapidly prototype. Users can test an idea or concept and complete verification in hardware without going through the lengthy manufacturing process of custom ASIC design. This allows users to make incremental modifications and iterate FPGA designs in hours, saving weeks. Commercial off-the-shelf (COTS) hardware provides different types of I/O connected to user-programmable FPGA chips. The increasing popularity of high-level software tools reduces the learning curve and abstraction layers, and often provides useful IP cores (pre-built functions) for advanced control and signal processing. 2.3 Cost The non-recurring engineering (NRE) cost of custom ASIC design far exceeds the cost of FPGA-based hardware solutions. The huge initial investment in ASIC design shows that OEMs need to ship thousands of chips each year, but more end users need custom hardware capabilities that enable the development of tens to hundreds of systems. The nature of programmable chips means that users can save on manufacturing costs as well as long lead times for assembly. System requirements change from time to time, but the cost of changing the FPGA design is negligible compared to ASCI's huge expense. 2.4 Stability Software tools provide the programming environment, and FPGA circuits are the real "hard" implementation of programming. Processor-based systems often contain multiple layers of abstraction that can schedule tasks and share resources among multiple processes. The driver layer controls hardware resources, while the operating system manages memory and processor bandwidth. For any given processor core, only one instruction can be executed at a time, and processor-based systems face the risk of tightly time-bound tasks taking over each other at all times. FPGAs, on the other hand, do not use an operating system, and have true parallel execution and deterministic hardware that focuses on each task, reducing the chance of stability issues. 2.5 Long-Term Maintenance As mentioned above, FPGA chips are field-upgradable without the time and expense involved in redesigning ASICs. For example, digital communication protocols contain specifications that can change over time, and ASIC-based interfaces can create maintenance and forward compatibility difficulties. Reconfigurable FPGA chips can accommodate future modifications. As a product or system matures, users can enhance functionality without spending time redesigning hardware or modifying board layouts.   Ⅲ New Applications of FPGA At present, the FPGAs mainly produced by Xilinx and Altera with the highest market share, which are all based on SRAM technology, and need to be connected to an external memory to save the program when in use. When powered on, the FPGA reads the data in the external memory into the on-chip RAM, and after completing the configuration, it enters the working state. When power off, the FPGA returns to a white chip, and the internal logic disappears. In this way, the FPGA can not only be used repeatedly, but also does not require a special programmer, but only a general EPROM and PROM programmer. So Actel, QuickLogic and other companies also provide FPGAs with anti-fuse technology, which can only be downloaded once. They have the advantages of anti-radiation, high & low temperature resistance, low power consumption and fast speed. They are widely used in military and aerospace fields. FPGA cannot be erased and written repeatedly, which is troublesome and expensive in the early stage of development. Lattice is the inventor of ISP technology, which has certain characteristics in small-scale PLD applications. Early Xilinx products generally did not involve military and aerospace markets, but now a number of products such as Q Pro-R have entered such fields.In the industrial field, FPGA chips are widely used in the industrial field, and are widely used in video processing, image processing, CNC machine tools and other fields to realize signal control and operation acceleration functions. With the development of intelligence and automation technology, the industrial field is gradually shifting from human resources as the core element to intelligent unmanned factories with automation as the core element.Smart electric vehicles will be the mainstream development direction of the automotive industry in the future. At present, the application of FPGA in automotive cameras and sensors is relatively mature. In the artificial intelligence system of automatic/intelligent driving vehicles, the applicability of FPGA will be the most suitable for processing sophisticated ADAS and autonomous driving. Figure 7. FPGA for Auto In the field of automotive electronic system interface and control, FPGA chips are used to control and drive electric vehicle motor control systems, connect various in-vehicle equipment such as driving systems, instrument panels, radar, ultrasonic sensors, etc. control. In the field of video bridging and fusion, FPGA chips can be used to realize functions such as signal bridging of multiple image sensors, 3D surround view video fusion, reversing auxiliary video, and assisted driving video.In the field of communication, the number of 5G base stations has increased, and the FPGA usage of a single base station has increased, driving the increase in FPGA demand. According to estimates, the FPGA consumption of a 5G single base station is expected to increase from 1-3 blocks in the 4G period to 4-5 blocks in the 5G period. Figure 8. RFSoC FPGA Board Target 5G eFPGA technology is superior to traditional FPGA solutions in terms of performance, cost, power consumption, profitability, etc., and can provide flexible solutions for different application scenarios and different market segments. The economic trend of increasing design complexity and falling equipment costs has stimulated the market demand for eFPGA technology.   Ⅳ Development Trend of FPGA First of all, with the commercialization of the new generation of communication technology, the demand for products such as communication base stations, servers, and intelligent terminals will further expand, thereby driving the increase in the market demand for FPGA chips. At the same time, smart cities, smart factories, and consumer electronics pay more attention to the functionality of various smart IoT devices, which will drive the wide application of FPGA chips in smart IoT devices. With the development of the Internet of Vehicles technology, the scale of the use of FPGA chips in the automotive industry will increase day by day to build a more complete Internet of Vehicles and realize smarter autonomous driving functions. Therefore, with the rapid penetration of 5G, the vigorous development of AI and the increasing trend of automotive intelligence, it is expected that the demand for FPGAs in the three fields of communication, AI and automotive electronics will continue to increase in the future, which will also promote The FPGA industry continues to grow.   Ⅴ FAQ 1. What is FPGA and why it is used?The acronym FPGA stands for Field Programmable Gate Array. It is an integrated circuit that can be programmed by a user for a specific use after it has been manufactured. ... These blocks create a physical array of logic gates that can be customized to perform specific computing tasks. 2. Is FPGA faster than GPU?The difference between GPU and FPGA performance is not a static factor, but it does depend on the size of the data set. A study by Sanaullah and Herbordt [7] revealed that FPGA can compute small samples of 3D FFT tens of times faster than GPU. The difference is less clear when the data set gets bigger. 3. Is FPGA faster than CPU?A FPGA can hit the data cell faster and more often than a CPU can do it meaning the FPGA causes more results to occur during an attack. It all goes faster when an FPGA is used. And as a side benefit, no trace of all this is left on the CPU because it's never touched when an FPGA is used. 4. Are FPGAs efficient?Efficiency and Power: FPGAs are well-known for their power efficiency. A research project done by Microsoft on an image classification project showed that Arria 10 FPGA performs almost 10 times better in power consumption. 5. Is FPGA programming hard?FPGA vendors have touted their wares as ideal replacements for DSPs, CPUs, and GPUs – even for all of them in a single device – but they are notoriously difficult for software engineers to program as they are not anything like a conventional processor. 6. What can you do with FPGAs?Uses for FPGAs cover a wide range of areas—from equipment for video and imaging, to circuitry for computer, auto, aerospace, and military applications, in addition to electronics for specialized processing and more. 7. What is the difference between processor and FPGA?Microprocessor vs FPGA: A microprocessor is a simplified CPU or Central Processing Unit. ... An FPGA doesn't have any hardwired logic blocks because that would defeat the field programmable aspect of it. An FPGA is laid out like a net with each junction containing a switch that the user can make or break. 8. What language is used to program FPGA?VerilogTraditionally, FPGAs are programmed using pro-level hardware-description languages such as Verilog or VHDL. 9. How many times can you program an FPGA?There is effectively no limit to the number of times a device can be reconfigured; the configuration is stored in SRAM, which has no write limit. most Fpgas can be passively loaded from a processor, one word at a time. That processor can get the FPGA image from anywhere. 10. What are the advantages of FPGA?FPGA advantagesLong-term availabilityUpdating and adaptation at the customerVery short time-to-marketFast and efficient systemsAcceleration of softwareReal-time applicationsMassively parallel data processing 11. How do you make an FPGA?FPGA design checklistMake sure you have plenty of time to spare.Find a decent computer.If you can afford it, add a big display.Decide which operating system to use.Consider using a virtual machine (VM).Select an FPGA vendor.Pick out a suitable development board.Select an embedded processor to use. 12. What is FPGA for beginners?FPGA stands for Field Programmable Gate Array. As you may already know, FPGA essentially is a huge array of gates that can be programmed and reconfigured any time anywhere. Huge array of gates is an oversimplified description of FPGA. FPGA is indeed much more complex than a simple array of gates. 13. What is FPGA in Verilog?FPGAs are nothing, but reconfigurable logic blocks and interconnects can be programmed by Hardware Description Language like Verilog/ VHDL to perform a specific functionality. 14. Do we need to program the FPGA once powered off?If you have a SRAM-based FPGA, like the Spartan 3, then you have to program it each time it is powered up. The reason for this is that the SRAM which stores the configuration is volatile and loses the programmed configuration after power is switched off. 15. How is FPGA different from microcontroller?One of the main differences between a microcontroller and an FPGA is that an FPGA doesn't have a fixed hardware structure, while a microcontroller does. While FPGAs include fixed logic cells, these, along with the interconnects, can be programmed in parallel by using HDL coding language.

CatalogIntroduction Ⅰ Flysky Transmitter and Receiver1.1 4-channel Flysky Transmitters1.2 Essential Features of Flysky Receivers  Ⅱ RF Transmitter vs RC Transmitter2.1 What is RF Transmitter?2.2 What is RC Transmitter?2.3 Differences between RC and RF Transmitters  Ⅲ Key Points of RC/RF Transmitter and Receiver3.1  How to Bind RC Transmitter and Receiver ?3.2 How to Pair Your RC Transmitter and Receiver?3.3 How to Extend the Range of a RF Transmitter and Receiver?3.4 How do RF receivers Synchronize on a Transmitter's Signal?3.5 8 Tips for Easier RC Transmitter Control  Ⅳ FAQIntroduction A flysky transmitter collects and decodes information, and a receiver displays it in audible and/or visual form for consumers to view or listen to. The radio is the most well-known and oldest invention to use this system.Ⅰ Flysky Transmitter and Receivervideo shows how to bind with Flysky Receivers  - iA6, X6B, iA6B, Fli14+, GT3B, FLIT10 - FS-i6 and FS-i6X Radio 1.1  4-channel Flysky TransmittersFlySky sells 4-channel transmitters, but while a 4-channel TX is adequate for simple RC cars, boats, and planes, a mini quad requires 6 or more channels.Channels 1–4 are used to control the actual movement of the craft, while the remaining channels are delegated to the radio's switches and pots (potentiometers) and are regarded as "Auxiliary Channels," denoted by the letters AUX 1, AUX 2, and so on.Aux channels on a quadcopter can be used to activate different flight modes and control various peripherals such as a lost model buzzer and LED light. With new technology being released regularly, the number of functions and peripherals that we can control from the transmitter grows by the day.Realistically, if you only have 6 channels available, you will quickly feel limited, so we have only included TXs with 6 or more channels.1.2 Essential Features of Flysky Receivers  TelemetryI believe that telemetry was an afterthought for FlySky, and given that most newer FCs come with an integrated OSD, who can blame them if they are focusing sales on the FPV market? In reality, telemetry is one of the 'bells and whistles' I mentioned earlier, and it is by no means required for the beginner.FailsafeAs you can see, there are some sacrifices that must be made when using a FlySky RX to ensure that you have an operational failsafe. Failsafe is probably not as important as the telemetry in an indoor model or a micro you use in the garden, but it is far more important. For some reason, the best RX FlySky makes for larger models (the FS-X6B) only offers a failsafe on the older PWM protocol, which is in my opinion absurd.As you can see, failsafe is not always available over specific protocols, depending on the RX. Failsafe is far more important than telemetry because it reduces the possibility of unexpected behavior in the event that the RX signal is lost. Take the time to ensure you're using a failsafe protocol!Ⅱ RF Transmitter vs RC Transmitter2.1 What is RF Transmitter?An RF transmitter is a type of electronic device that uses an antenna to convert analog signals to digital signals. They have an embedded storage memory that aids in the storage of information, which is then converted by an RF receiver as required by the user. RF transmitters operate at various frequencies, allowing signals to be transmitted at the desired frequency range. They are primarily used in a variety of applications ranging from electronic toys to telecommunication devices and satellites.2.2 What is RC Transmitter  ?2.4GHz radio control transmitters (TX) for all RC applications. Stick and wheel transmitters are available from Etronix and are suitable for use in automobiles, aircraft, boats, and drones.2.3 Differences between RC and RF Transmitters  RC stands for “radio control”.RF stands for “radio frequency”.A radio frequency is used by radio control transmitters to transmit a signal. Radio frequency is used by TV and radio stations to transmit a different type of signal.Radio frequency is a very broad term that refers to electromagnetic signals with frequencies ranging from 100kHz to 100GHz. Radio control is a subset of radio frequency usage.Ⅲ Key Points of RC/ RF Transmitter and Receiver3.1 How to Pair your RC Transmitter and Receiver?Most modern RCs use 2.4 GHz TX and RX that must be paired in the same way that a Bluetooth device is paired with a computer or phone. The RX  has a couple of pins that are connected by a special binding plug. A bind button or switch is located somewhere in the TX. By shorting two pins, you can activate the RX while the TX is in bind mode. When the bind is complete, the LED will usually flash quickly and then glow steadily, and the RX will respond to stick motions. The bind plug is then removed from the RX, and the RX will begin listening to your receiver once it detects its unique transmitting protocol.When the TX is turned on, it will first listen for an available channel before transmitting on it, while the RX will scan channels until it hears the transmitter to which it has been bound. There is usually a brief "boot up" period before the link is established, lasting about a second. Although it is still legal to use old equipment such as crystals and frequency control boards, they are largely obsolete.3.2 How do You Increase the Range of an RF Transmitter and Receiver?Several ways are available.Increase the power of the transmitter. This is not always legal.Utilize a single sideband (SSB) AM modulation scheme to direct more power to a transmitter signal (legally).For the transmitter and receiver, use a lower frequency carrier. Longer wavelengths frequently have a greater range than higher frequencies.Use a higher modulation percentage to produce a signal that is easier to decode at the receiver.Tune the transmitter antenna if it is not already well-tuned. Use a better ground plane if possible, or place the transmitter closer to a natural ground plane.Raise the transmitter antenna's height above the ground.Utilize a directional antenna with gain pointing in the direction(s) of the intended receivers.Extend the range beyond-line-of-sight by utilizing ionosphere reflections. This is not always reliable because it is affected by natural ionosphere changes.Utilize a repeater at a point halfway between the transmitter and the receiver. This could be anywhere, including a mobile device, a mountain top, a tall building, or even a satellite.Raise the height of the receiver antenna above the ground.Install a better ground plane or place the transmitter near a natural ground plane, such as a lake.Use a directional receiver antenna that is pointed in the direction of the desired transmitter and is tuned to the correct frequency.Use a receiver with a higher gain, lower noise, and greater sensitivity.Use a digital data encoding strategy with data correction capability, a more robust, slower transmission data encoding scheme with multiple, redundant transmissions, and a receiver capable of decoding and error-correcting that data.Utilize multi-band transmission to compensate for poor radio propagation conditions.3.3 How do RF Receivers Synchronize on a Transmitter's Signal?Synchronization is usually accomplished in stages.Step 1 Align the frequencies of the transmitter and receiver. In the days before synthesized oscillators, improving frequency stability required some serious engineering. Typically, the last resort was some form of automatic frequency control, or AFC, which used a pilot carrier that was transmitted alongside the actual information carrier.Step 2Advances in frequency control enabled the AFC to be removed from many applications. Today, most frequency error correction is done in the demodulator circuit.Step 3Demodulate the information bits carried by the modulated wave. This results in demodulated data, which can then be analyzed for patterns or embedded clock information.This data is used to adjust the phase of a locally generated clock signal so that it corresponds to the data elements received.In some implementations, clock recovery information is embedded in the data itself, whereas in others, special patterns or bit sequences are dedicated to clock recovery.Step 4 Properly align the data streams with the demodulator so that the actual information can be retrieved, a process known as "data" or "frame" synchronism. 3.4 How to Bind RC Transmitter and Receiver ?Most RC transmitter manufacturers provide pre-programmed transmitters for their respective receivers. However, if you need to replace the components, you can do so by following these steps. The tools you'll need include an accessible receiver, a charged battery in the model, and charged batteries in the transmitter.Syncro System (Kyosho)The Syncro system is commonly used in a variety of models such as the Fazer Rage, Fazer Tl drift car, Outlaw Rampage, and many others. The binding tick requires you to hold down the bind button while powering up the model.You'll notice the transmitter LED flashing quickly. Then, before releasing the bind button, turn on the transmitter. The receiver LED will then re-light to ensure that the process is complete.TQi Top Qualifier (Traxxas)Another ultra-ergonomic high-performance system was found on the Merc G500. Roveris Traxas' radio is TEXAland Roveris Traxas. To rebind this radio, press and hold the red setbutton on the top of the RC transmitter while turning it on; the led should gradually flash red.You can seat the release button at the same time. Press and hold the link button on the receiver end while turning on the speed controller. Finally, when it is powered up, you can let go of it. You can take it for granted if you notice the receiver and transmitter lights turn green.Tactic TTX300 Binding (Axial)This transmitter and receiver system is found on the RTR Axial SCX10il. To bind this, turn on both the receiver and the transmitter, as well as the RC car.Then, on the receiver's box, press and hold the link button. You must press and hold it until it turns red, just before it turns off. Finally, its receiver LED will flash once before returning to a steady state.3.5 8 Tips for Easier RC Transmitter Control  Although most transmitters provide adequate grip and comfort, there are a few tricks you can use to improve them. Improving grip can improve how well you drive your vehicle, which is a definite advantage if you like to compete. Here are a few RC Transmitter Control  tricks that you can use to gain an advantage over your competition.STEERING WHEEL MODS Tennis Racket Grip Tape Wrapping the transmitter's grip with tennis racket grip tape will help wick away any moisture created by your hand, reducing the the'slip' factor. As a result, the transmitter is easier to hold without fear of dropping it. You won't have to grip as tightly, which will reduce hand fatigue. Furthermore, because the tape is thin, it will not change the size of the transmitter grip. This is a plus if you like the size and feel of the stock transmitter in your hand. You can also choose from a variety of colors for the grip tape, which will help you identify your radio.Steering wheel changeAftermarket steering wheels are available from companies such as Duratrax, Hot Racing, and Dynamite if your steering wheel is worn or you want to try something different. Not all foam is the same, and you may find one that suits you better.Improved GripThere are also steering wheel grips that can be added to improve control and reduce fatigue. Pro Grips from Xtreme Racing are designed to fit over your existing steering wheel. The scallop shape gives your fingers a place to rest, and the grips don't require glue to stay in place.Drop Down Kit The manufacturer of your transmitter may offer a drop down steering wheel kit. These kits lower the steering wheel so that your hands are in line with each other, which may be a more comfortable position for you.Trigger Tricks 1.I've discovered that some triggers are so smooth that your finger can slip off of them. Fix this with a wrap of racket grip tape.2. A length of fuel tubing is an easy fix for triggers that don't provide a tight feel for your finger, which can impair braking responsiveness. To help close the opening for your finger, slide the fuel tubing over the forward section of the trigger. This trick will also increase the friction on your finger.Self-adhesive FoamIf you want to make the grip larger and/or contour it to your hand, some self-adhesive foam can help. It may take some trial and error to get it exactly how you want it, but it is worth the time to get it right. Once in place, cover it with grip tape to make it more secure.Optional GripsIf you read the instruction manual for your transmitter, you will most likely discover that the manufacturer provides optional transmitter grips. They are typically available in larger or smaller sizes than stock and are simple to install on the transmitter.Ⅳ FAQ1. Are Flysky transmitters any good?A cost effective and overall great product. The transmitter feels a little cheap, but its performance works just as advertised. ... Overall, I say this product is a good buy. It's simple and relatively cheap (compared to other models), but performs great!2. Can you use any transmitter with any RC car?Yes, RC transmitters and receivers are interchangeable, so that you can use transmitters and receivers of different brands, and they will work perfectly.3. Is FlySky and Frsky the same?In my view, the components of the frsky stations have a much higher quality than the flysky ones. ... But if yours is going to fly more continuously, you are looking for reliability because you already have a more serious and more expensive model, I recommend that you acquire a Horus or taranis type frsky station.4. What is the range of a 2.4 Ghz RC transmitter?about 300 feetThe 2.4GHz version of the HumRC Series is about 300 feet (90m) for remote control applications.5. Are FlySky and Spektrum compatible?But Spektrum transmitters cannot talk to FlySky receivers - ever. ... But Spektrum transmitters cannot talk to FlySky receivers - ever. Spektrum transmitters require receivers that use the DSMX or DSM2 algorithms. You need the Spektrum AR610 receiver (or equivalent) in order to bind with your Spektrum DX6 transmitter.6. Is FlySky compatible with DSMX?You would need to put a Spektrum compatible RF module in the FlySky transmitter. ... If the flysky uses the spektrum dsm2/dsmx then yes.7. Does FlySky have telemetry?Spare receiver for the FlySky i6 Transmitter. ... Voltage telemetry built in when paired with the i6 transmitter. This receiver features dual antennas for optimal performance and no fear of interference.8. Is Flysky GT5 waterproof?The gyro function is surprisingly valuable in both and you can get a bunch on amazon real cheap. however, I recommend using some conformal coating or corrosion -x as they are not waterproof. I use the FS-GT5 with the FS-BS6 receivers and they work great in my cars and in my boat.9. Can you bind any transmitter to any receiver?You can use a transmitter with any receiver. BUT you have to have a way of changing the antenna when you transmit. There are antenna relays for this purpose that will automatically make the change for you. The power of the transmitter would quickly destroy your receiver. 

Introduction The introduction of grounding technology was originally a protective way to prevent electrical or electronic equipment from being struck by lightning. At the same time, it is also an effective means to protect personal safety. When the phase line (such as poor wire insulation, aging, etc.)  touches the equipment shell for some reason, dangerous voltage will be generated on the equipment shell, thus the generated fault current will flow through the PE line to the ground, thus playing a protective role. With the development of electronic communication and other digital fields, only considering lightning protection and safety in the grounding system is far from meeting the requirements. Electrical Grounding Explained | Basic Concepts Catalog Introduction Ⅰ Basic: Q&A Related to Electrical Ground Ⅱ DC Power Supply Ground 2.1 Basic Overview 2.2 DC Power Supply Ground Analysis with Diagrams 2.3 Ground Bounce for Buck Converters 2.4 Ground Bounce for Boost Converters 2.5 Summery Ⅲ Useful Concepts for Grounding Analysis Ⅳ Conclusion Ⅴ FAQ Ⅰ Basic: Q&A Related to Electrical Ground The signal between each device needs a "ground" as the reference ground of the signal. Moreover, with the complexity of electronic equipment, the signal frequency is getting complicated. Therefore, in the grounding design, special attention must be paid to electromagnetic compatibility issues such as mutual interference between signals. Otherwise, improper grounding will seriously affect the reliability of system operation. Here the following are doubts that may arise in the power grounding. Q1: What is the definition of grounding?A: As for grounding concepts, to line engineers, the term usually means "reference point for line voltage". For system designers, it is often a cabinet or rack. For electrical engineers, it means green safety ground or connection to the earth. A more general definition is "A ground is a low impedance path for current to return to its source", and the key points are "low impedance" and "passage". Q2: What are the common grounding symbols in circuit?A: PE, PGND, FG-protective ground or chassisBGND or DC-RETURN-DC-48V (+24V) power supply (battery) returnGND: working groundDGND: digital groundAGND: analog groundLGND: lightning protection ground Q3: What is the appropriate grounding method?A: There are many ways to ground, including single-point grounding, multi-point grounding and mixed types of grounding. Among them, the single is divided into series single-point grounding and parallel single-point grounding. Generally speaking, single-point grounding is used for simple circuits, while grounding distinction between different functional modules, and multi-point grounding or multi-layer boards (complete ground plane layer) are used in low-frequency (f10MHz) circuits. Q4: Why should the analog ground and digital ground be separated?A: Both the analog signal and the digital signal return to the ground, the digital signal changes fast with large noise, while the analog signal needs a clean ground reference to work. If the analog and digital grounds are mixed, noise can affect the analog signal.According to the above mentioned, the analog ground and the digital ground should be processed separately, and then connected together through thin wires, or together at a single point. The general idea is to try to block the noise on the digital ground from flowing to the analog ground. Of course, this is not a very strict requirement that they must be separated, because it depends on the actual situation. Q5: How to ground the signal on the board?A: Under normal circumstances, it is best to use the nearest ground when designing, and after a complete multi-layer board design, it is very easy to ground common signals. The basic principle is to ensure the continuity of the traces and reduce number of vias, close to ground plane or power plane, etc. Q6: How to ground the interface devices of the board?A: Some single boards have external input and output interfaces, such as serial port connectors, network port connectors, etc, if they are not properly grounded, it will also affect normal work, such as network port interconnection errors, packet loss, etc., and will become an external source of electromagnetic interference, sending the noise inside the board to the outside. Generally speaking, an independent interface ground will be divided, and the connection with the signal ground will be connected by thin traces, and a o small resistance or 0ohm resistor can be connected in series. Thin traces can be used to block signal ground noise from passing to the interface ground. Similarly, the filtering of interface ground and interface power should also be carefully considered. Q7: How to ground the shielding layer in the cable with shielding layer?A: The layer of the shielded cable must be connected to the interface ground of the single board, not the signal ground. This is because there are various noises on the signal ground. If the shielding layer is connected to the signal ground, the noise voltage will drive the common mode current along the shielding. Therefore, cables with unreasonable design are generally the largest noise output source of electromagnetic interference.   Ⅱ DC Power Supply Ground 2.1 Basic Overview In power supply design, safety is often in the first place, and the same is true in switching power supplies. Grounding can protect the personal safety of users and ensure the normal operation of power equipment. So what is the appropriate grounding method in switching power supplies? What are the common ground symbols in circuits? This article will popularize the grounding basic in DC power supplies.DC-DC is a commonly used power supply circuit in electronic hardware design. It has high efficiency in realizing high input voltage and low output voltage. It is widely used, from power adapters, mobile phone chargers, and internal power conversion of electronic equipment to DC-DC circuits. Each semiconductor manufacturer has its own DC-DC chips, and also there are many optional chips. For a well-designed DC-DC circuit, not only the peripheral resistance, capacitance, but also the inductance parameters of the DC-DC circuit should be considered. There are also high requirements for the PCB layout design. This paper proposes a method to guide the grounding in the PCB layout from the perspective of the current flow in DC circuits. 2.2 DC Power Supply Ground Analysis with Diagrams Circuit grounding looks simple in a circuit schematic, but the actual characteristics of a circuit are determined by the layout of its PCB. And the analysis of the grounding point is very difficult, especially for the DC-DC converter circuit, the grounding point of the circuit will gather a large current that changes rapidly. When grounded nodes move, system performance suffers and the system radiates EMI. Here a good understanding of the physical nature of "ground" induced ground noise can provide an intuitive understanding of ground noise reduction problems.The change of the transmission current in the ground loop will generate a magnetic field in the loop. The magnetic field strength is proportional to the current, and the magnetic flux is proportional to the product of the loop area and the magnetic field strength, which is expressed by the formula: Figure 1. Right Hand Rule Suppose there is a sudden break in the current loop, as shown in Figure 2. When the switch is turned off, the magnetic flux disappears, which will generate a large transient voltage along the wire. If part of the wire is a grounding return pin, the voltage referenced to the ground level will have a spike, resulting in a false signal in any circuit that uses that pin as a ground reference. Figure 2. Function of Start Switch The traces on the PCB circuit board are not ideal wires and have resistance. 1 ounce (oz) copper has a resistance of 500 microohms/square, so a 1 amp change in current will only produce a bounce voltage of 500uV/square -- the problem only exists if you use long thin traces or daisy chain grounds or Precision electronic circuits.The best way to reduce ground bounce in a DC-DC switching circuit is to control the magnetic flux variation—minimizing current loop area and loop area variation. The principle of DC-DC circuit buck or boost is to use electronic switches to quickly switch to charge and discharge the energy storage element to achieve voltage conversion, and at the same time change the loop area of the current in the circuit, resulting in ground bounce and electromagnetic radiation.In some cases, as shown in Figure, the current remains constant, while the switching causes a change in the loop area and therefore a change in the magnetic flux. In switching state 1, an ideal voltage source is connected to an ideal current source through an ideal conductor. In addition, current flows in a loop that includes a ground return.In switch state 2, the same current flows in different paths when the switch changes position. The current source is DC and there is no change, but the loop area has changed. A change in the loop area means a change in the magnetic flux, so a voltage is generated. Because the ground loop is part of the change loop. Figure 3. Figure Loop Area In the case of switching changes, the loop area changes. Everywhere along the wire in the lower left, when the current I1 becomes 0, a voltage is generated where the magnetic field disappears. 2.3 Ground Bounce for Buck Converters The buck converter (step-down converter) circuit is very similar to the circuit structure in Figure 3 above, and the circuit of the step-down converter is simplified, as shown in Figure. Figure 4. Step-down Converter Circuit At high frequencies, a large capacitor such as the input capacitor Cin of the step-down converter can be regarded as a DC voltage source. Similarly, an inductor such as the output inductor LBuck can be regarded as a DC current source. These approximations help to visualize understanding and theoretical analysis.As shown in Figure 5, when the switch alternates between the two positions, the change in the path through which the current flows causes a change in the magnetic flux. The large inductor LBuck keeps the output current approximately constant. Similarly, the large capacitor Cin holds the voltage approximately equal to Vin. Since the voltage across the input lead inductance does not change, the input current also remains approximately constant. Figure 5. Effect of Switch on Loop Area Although the input current and output voltage are essentially constant, when the switch is switched from position 1 to position 2, the total loop area rapidly changes by half. Loop area changes imply rapid changes in magnetic flux, causing ground bounce along the loop circuit.In practice, a buck converter consists of a pair of semiconductor electronic switches, as shown in Figure 6. Although the complex procedure increases in each figure, the analysis method for ground bounce caused by changes in magnetic flux remains simple and intuitive. Figure 6. Magnetic Flux Changes Cause Ground Bounce The fact that changes in magnetic flux create voltages along the ground loop raises an interesting question: where is the real ground? Because ground bounce means that, to some ideal point called ground (that point needs to be defined), a bounce voltage is created on the ground return trace. In a power regulator circuit, the real ground should be connected to the low-voltage side of the load. After all, the purpose of a DC-DC converter is to provide a stable voltage and current to the load. All other points on the current loop are not true ground, but the part of ground loop.Since the low-voltage end of the load is grounded and the change in the loop area is the cause of the ground bounce, then reducing the ground bounce and electromagnetic radiation, and optimizing the grounding of the circuit are to minimize the current loop area in the DC-DC circuit. Here is a way to optimize the layout. For example, the location of the input capacitor, output capacitor, and energy storage inductor reduces the current loop area. Figure shows how to carefully place the input capacitor Cin to reduce the loop area and ground bounce. Figure 7. Reduce Ground Bounce Capacitor Cin in Figure bypasses the high-side switch on the top layer of the PCB directly to both ends of the bottom low-side switch, thereby reducing the variation in loop area and isolating it from the ground return. When the switch switches from one state to another, from the bottom of Vin to the bottom of the load, there is no loop area change or switch current change. Therefore no ground bounce occurs in the ground loop.Figure is an unreasonable PCB layout. When the high-side switch is turned on, the DC current flows along the red loop of the outer ring. When the low-side switch is turned on, the DC current flows along the blue loop. It can be seen that this circuit layout produces a large loop change when the switch changes, causing a change in the magnetic flux, resulting in ground bounce and electromagnetic radiation interference. Figure 8. Unreasonable Layout For the clarity, in single-layer PCB routing, even using a second-layer monolithic ground plane cannot solve the bounce caused by grounding. Figure 9 is a simple box to illustrate that the ground plane cannot solve the problem. Here we use a double layer PCB to add a bypass circuit at the top level power line vertical. Figure 9. Ground Floor In the Figure 9 (a), the ground plane is monolithic and uncut. The top layer print current flows through the capacitor, through the via, and to the ground plane. Because AC always flows along the path of least impedance, ground return current returns to the power source around the corners of its path. So when the amplitude or frequency of the current changes, the magnetic field of the current and its loop area change, thereby changing the magnetic flux. The regularity of current flow along the path of least impedance means that ground bounce can occur even with a monolithic ground plane - independent of its conduction.In the Figure 9 (b), a properly cut ground plane limits the return current to minimize loop area, thus greatly reducing ground bounce. Any residual ground bounce voltage developed within the cut return line is isolated from the common ground plane.The PCB layout in Figure 10 uses a double-layer PCB to mount the input capacitor and two switches on islands in the ground plane. This wiring doesn't have to be the best, but it works well and speaks to key points. It should be noted that the loop area surrounded by the red and blue currents is large, but the difference between the two loop areas is small. A small change in loop area means a small change in magnetic flux—small ground bounce. However, in general, keep the loop area small. Figure 10. is just to illustrate the importance of AC current path matching. Figure 10. Converter Layout   Additionally, ground bounce along any ground loop is limited by ground cutting within ground loop islands where magnetic fields and loop areas vary. Also, it may appear at first glance that the input capacitance Cin is not located between the top-level high-side switch and the lower-level low-side switch shown in Figure 10. Although physical proximity can be fine, what really works is the electronic proximity achieved by minimizing the loop area. 2.4 Ground Bounce for Boost Converters A boost converter (step-down converter) is actually a reflection of a buck converter, as shown in Figure 11, where the output capacitor must be placed between the top high-side switch and the bottom low-side switch to minimize loop area change. Figure 11. Changes in Loop Area In the same way that a buck converter places Cvin at a critical position, a boost converter places Cvout at a key position. 2.5 Summery The ground bounce voltage is mainly due to changes in the magnetic flux. In a DC-DC switching power supply, the magnetic flux variation is caused by switching the DC current at high speed between different current loop areas. But careful placement of the buck converter's input capacitors and the boost converter's output capacitors, and a good cut of the ground plane can isolate ground bounce. Pay attention to, it is important to be careful when cutting the ground plane to avoid increasing the loop area for other return currents in the circuit.Another reasonable layout should place the real ground on the bottom layer connecting the load, which will not cause changes in loop area or current. Any other point related to conduction can be called "ground", but it's just a point along the return path.   Ⅲ Useful Concepts for Grounding Analysis If you follow the basic concepts, you will have a clear idea of what will cause ground bounce. Figure 12. shows that two conductors that are perpendicular to each other are not subject to the mutual influence of the magnetic field. Figure 12. Two Conductors Perpendicular to Each Other   The magnetic field lines created around two parallel wires carrying equal currents in the same direction traditionally cancel each other out between the two wires, so the total energy stored by the two wires is less than the energy stored by one wire alone. Therefore, the inductance of PCB wide traces is smaller than that of narrow traces. Figure 13. Two Parallel Wires with Current Flowing in Same Directions   The magnetic field lines generated around two equal conductors carrying equal currents in opposite directions cancel each other out of the two conductors, and strengthen between the two conductors. If the inner loop area is reduced, so does 4the total magnetic flux. This phenomenon can explain why the return current of the AC ground plane always flows under the trace conductors on the top layer of the bath. Figure 14. Two Parallel Wires with Current Flowing in Opposite Directions Figure 15. shows why corners add inductance. A straight wire only sees its own magnetic field, but at the corners, the magnetic field of a vertical wire is also visible. Therefore, the corners store more magnetic field energy, and their inductance is greater than that of straight wires. Figure 15. Add Inductance at the Corners Figure 16. shows that cutting the ground plane under the transmission line conductor increases the loop area by diverting the loop current, thereby increasing the loop size and contributing to ground bounce. Figure 16. Return Current Flows Along the Path of Least Impedance   Figure 17. Effect of Component Orientation   Ⅳ Conclusion Ground bounce has always been a potential problem. For monitors or TVs, it means the image is noisy, for audio equipment it means the noise floor. In digital systems, ground bounce can cause calculation errors -or even system crashes. Careful estimation of parasitic elements and simulation are effective methods for predicting the magnitude of ground bounce.First, when designing the PCB, the low-voltage side of the load should be set to true ground. Then, replace the large inductors and capacitors with current and voltage sources to simplify the circuit dynamics. Observing the current loop under each switch combination, the loops should be made to overlap, and if this is not possible, an island should be carefully cut out in the ground plane to ensure that only islands of DC inflow and outflow are present.In most cases, good grounding performance can be obtained with these efforts. If that doesn't work, the resistance of the ground plane should be considered first, then the displacement currents flowing across all switches and parasitic capacitors entering the return path. In short, no matter what circuit, the principle is the same, that is, to reduce the loop area and its difference when the switch changes.   Ⅴ FAQ 1. Does power supply need to be grounded?While it will likely be fine (I've run many computers in old houses that had no grounding), it's not advised. A static charge will build up, and depending on where it discharges may cause damage to the electronics. 2. What is the purpose of a ground wire?The ground wire offers an additional path for the electrical circuit to flow into the earth so as to not endanger anyone working with the electricity nearby in the event of a short circuit. Without ground wire, your body could instead complete the ground path and may cause shock or electrocution. 3. Which wire is ground on power supply?In a DC circuit, the convention in most of the world is that black is the “ground” and any other color carries a signal or power rail of some sort, with red and yellow being popular for power wiring, but it can really be any color on any particular connector. For example, for a typical PC “ATX” power supply. 4. What is the purpose of a ground?Grounding gives electricity the most effective way to return to the ground via your electrical panel. A grounding wire gives an appliance or electrical device a safe way to discharge excess electricity. 5. Should you ground the negative of a DC power supply?As long as both the negative terminal of the LED and the negative terminal of the battery both have good enough connections to ground then the ground will carry enough current between the two connection to complete the circuit and light the LED. The same applies in the mains electricity supply. 6. How do I know if my power supply is grounded?Insert one probe of the circuit tester into the small slot and the other probe into the large probe. If the circuit tester lights up, you have power to the outlet. Now place one probe in the small slot and the other probe into the "U" shaped ground hole. The indicator should light up if the outlet is grounded. 7. Can you ground yourself by touching PSU?It looks pretty, but it's impossible to ground yourself to a case that has no bare metal. Instead, I just installed my power supply and touched the ground prong every now and then. All that said, if all you're doing is touching a metal part on the computer, you aren't really grounding yourself. 8. Can I tie the neutral and ground together?No, the neutral and ground should never be wired together. This is wrong, and potentially dangerous. When you plug in something in the outlet, the neutral will be live, as it closes the circuit. If the ground is wired to the neutral, the ground of the applicance will also be live. 9. What is ground in DC circuit?Traditionally, "ground" is the lowest potential in a circuit, e.g. the minus side of a battery or DC supply. 10. What happens when electricity goes to ground?The majority of the energy of the lightning discharge is dissipated in the air as it travels from the clouds to the ground through the air. The remainder is dissipated in the ground in the area surrounding the location of the strike, over a fairly short distance. 11. What is difference between earthing and grounding?Earthing and grounding are similar terms. ... The main difference between earthing and grounding is that the earthing refers that the circuit is physically connected to the ground with Zero Volt Potential. But, grounding refers that the circuit is not physically connected to ground, but still has zero potential. 12. Does a DC power supply need a ground?The answer comes from the NEC section 250.162, referring to the grounding of two-wire DC systems, which includes the 5V and 24V outputs, depending on your case. ... So, the short answer for a 24V DC system is no, the output is not required to be connected to ground. 13. How do you ground a DC power supply?You ground the device by connecting a grounding cable to earth ground and then attaching it to the grounding point on the DC power supply. You must provide the grounding cables. The cable lug used on the grounding cable should have a #10 stud hole and accommodate a minimum of 12-AWG wire.

IntroductionⅠ What is the Backlit Keyboard? 1.1 Advantages of the Backlit Keyboard 1.2 Disadvantages  of the Backlit KeyboardⅡ How to Enable and Disable a Backlit KeyboardⅢ Compact Backlit Keyboard w/Force Sensing Resistor (USB) (Black) | SLK-79-FSR-USB by iKey    3.1 How Does a Force Sensing Resistor (FSR) Work?    3.2 How do Force Sensing Resistors Measure Force?    3.3 How do You Calibrate a Force Sensing Resistor?    3.4 How are Force Sensing Resistors Made?    3.5 Matrix or Single-Point Force Sensing Resistors    3.6 How are Force Sensing Resistors Used?Ⅳ Factors to Consider Before Purchasing a Backlit Keyboard    4.1 Price    4.2 Increased Power Usage    4.3 Brightness    4.4 RGBⅤ How Much does a Backlit Gaming Keyboard Cost?Ⅵ Frequently Asked Questions about Backlit KeyboardIntroductionThe term "backlit keyboard" refers to a keyboard that has a light beneath the keys. In low-light situations, the backlight illuminates the letters and symbols on the keys to make them visible. Because the print on the keys is semi-transparent, the light will pass through it like a window. Read this article to learn how to choose a backlit keyboard quickly.Video: Backlight KeyboardsⅠ What is the Backlit Keyboard?A backlit keyboard, also known as an illuminated keyboard or a backlit gaming keyboard, is one that has lights inside it. The lights illuminate the area behind and around the keys, making them visible in low-light or dark settings. For energy efficiency and increased brightness, the light source is typically made up of mini LED light bulbs. Backlit gaming keyboards are popular among computer gamers, but they can also be used for general computing tasks. G.SKILL 's multicolor backlit gaming keyboard is shown below. 1.1 Advantages of the Backlit KeyboardThe distinction between a backlit keyboard and a regular keyboard is that the backlit keyboards can be used in the dark because they are illuminated from behind the keys.The characters associated with each key on regular boards are simply printed on and do not light up. Backlit keyboards  are therefore the most versatile option.You may have one or more colors depending on the keyboard supplier and model.A colorful backlit keyboard is a way to go for the gamer or the person who wants to add a little flair to their computer hardware setup.While these keyboards do have a more youthful feel to them, they are suitable for anyone who is young at heart.In general, the F and J keys have raised lines on them if you look at your keyboard (you may have to feel your keyboard).It's supposed to help you navigate the board even when the lighting isn't ideal.To work properly, you must, of course, know how to type efficiently and not just with your pointer finger (aka index finger).Some argue that efficient backlighting is the answer.Laptops with lights can be both functional and attractive.Learn more about illuminated keyboards as the ultimate gaming, editing, or programming accessory. 1.2 Disadvantages of the Backlit KeyboardFigure 1 Backlit keyboardThey cost more than other types of keyboards. Most models with key lighting start around $800 and rise from there - sometimes dramatically.Illuminated keyboards use more energy than standard keyboards. It can drain your battery faster if it is not plugged in and charging.Ⅱ How to Enable a Backlit KeyboardTouching the keys or across the edge of the keyboard usually activates the backlit feature. When the keys or keyboard edges are not touched, the lights automatically turn off after a short period of time. Turning off the lights automatically helps to conserve battery energy, extending battery performance between charges.Backlit keyboards for laptops and desktop computers may also include special keys or FN keys for permanently turning the backlight on and off, as well as the ability to change the color. The special or FN key to press on a keyboard varies depending on the manufacturer of the keyboard or laptop.In the Windows Mobility Center, most new PC laptops allow you to change the backlighting on the keyboard. On Dell laptops, this is frequently Fn+F10 or simply F10. Fn+Spacebar is the hidden key for adjusting the backlit keyboard  on Lenovo laptops.Ⅲ Compact Backlit Keyboard w/Force Sensing Resistor (USB) (Black) | SLK-79-FSR-USB by iKeyThe SLK-79-FSR-M keyboard was created for mobile applications that require a small footprint. The SLK-79-FSR-M, which includes an integrated force sensing resistor pointing gadget with dual left-click capability, packs a lot of power into a small package. The SLK-79-FSR-M includes backlit keys for working in low-light environments. The SLK-79-FSR-M, like the other iKey keyboards, has sealed industrial silicone rubber keypads and sturdy ABS polycarbonate cases.Features:12 Keys for FunctionPointing Device With Integrated Force Sensing ResistorKeyboard with Red BacklightConfigurations for USB and PS/2 are available. 3.1 How Does a Force Sensing Resistor (FSR) Work?In recent years, printed, thin, and flexible sensors have created quite a stir in the design engineering community. This is largely due to the proliferation of smart, lightweight, and energy-efficient technologies that have become ingrained in our daily lives. Naturally, when designing these small but powerful devices and products, the embedded components that make them game-changers should share the same characteristics.Force sensing resistors (also known as printed force sensors or force-sensitive resistors) are a large and expanding class of embedded components, with many new sensor types introduced in recent years. Force sensing resistors    , on the other hand, are not a new technology. For decades, force-sensing resistors have been used as an embedded component.3.2 How do Force Sensing Resistors Measure Force?Most engineers know that the formula for force is an object's mass multiplied by its acceleration (or, F=M*A) or applied pressure multiplied by contact zone (F=P*Area). Newtons (N), pound-force (lbf), and other engineering units are used to represent "F" in these equations.Figure 2: When a force sensing resistor is applied, the conductance response as a function of force is linear.Pressure sensor resistors are not pre-calibrated to correlate a force reading to a known technology unit on their own. The force measurement result captured by a force sensing resistor. On the other hand, can be correlated to the applied force via a calibration procedure.Piezoresistive sensing technology is a force-sensing resistor, This means that they are passive elements that serve as variable resistors in an electrical circuit. As illustrated in Figure 1, when the sensor is unloaded, it has a high resistance (on the order of Megaohms (M)) that decreases as force is applied (usually on the order of Kiloohms (K)). When the inverse of resistance (conductance) is considered, the thermal conduction response as a function of force is linear within the sensor's specified force range.3.3 How do You Calibrate a Force Sensing Resistor?Force sensing resistors  can really be calibrated with as few as two-to-three known loads due to their resistance/conductance linear relationship.Furthermore, if the circuit is built with adjustable components, the sensor's sensitivity can indeed be adjusted for optimal performance in the specific force range.3.4 How are Force Sensing Resistors Made?A semi-conductive material – or semi-conductive ink – is sandwiched between two thin substrates to form force-sensing resistors. As illustrated in Figure 3, there are two types of force sensing resistor technologies: Shunt Mode and Thru Mode.Figure 3:  The differences between shunt and thru mode force sensing resistor technologies.Force sensing resistors  in the shunt mode are polymer thick-film devices made up of two membranes separated by a thin air gap. One membrane contains two sets of interdigitated traces that are electronically isolated from one another, while the other is coated with a special textured, resistive ink.Thru mode force-sensing resistors  are flexible printed circuits with two outer substrates of polyester film. Above and below a pressure-sensitive layer, silver circles with traces are positioned, followed by a conductive polymer. The two layers of the substrate are laminated together with an adhesive layer. 3.5 Matrix or Single-Point Force Sensing ResistorsFigure 4: Examples of different force sensitive resistor technologies.ForceSensing resistors  can be configured as single-point force sensors or as a matrix array to capture pressure distribution over a large area. Pressure mapping technology refers to the use of force-sensing resistor  matrices.Tekscan's FlexiForceTM sensors are a type of thru mode force-sensing resistor. This technology's flexibility, combined with its operating capabilities and ability to operate on simple circuitry, makes it an excellent choice for embedding into smart devices with limited space and power. FlexiForce sensors are also extremely adaptable. Size, shape,  electrical termination, electrical termination, sensitivity,  and operating temperature can all be customized to meet the needs of your application. 3.6 How are Force Sensing Resistors Used?While there are new applications for force-sensing resistor technology every day, the majority of them fall into one of four categories:Detecting or measuring the rate at which a force changes.Detecting or measuring a change in force relative to another object.Touch and/or contact detectionDetecting force thresholds to initiate some kind of action (e.g., IoT applications)This short video gives you a better visual understanding of the various applications for force sensing resistors, specifically FlexiForce force sensing resistors.Are you interested in purchasing force sensing resistors? Ⅳ Factors to Consider Before Purchasing a Backlit KeyboardBefore purchasing a system with a backlit keyboard, you should think about a few things. The following sections go over each of them:4.1 PriceBacklit keyboard laptops are significantly more expensive than those without. As a result, it is recommended that you only invest in a feature if you are certain that it will benefit you and improve your user experience. It is recommended that you skip this feature if you rarely use your computer in dimly lit environments or if you can type without looking. 4.2 Increased Power UsageYour battery  percentage will quickly be depleted by backlit keyboard  s. As a result, if you value durability over aesthetics, you should avoid purchasing a laptop with a backlit keyboard,  However, if you don't mind having your system plugged in the majority of the time, the reduced battery  life shouldn't be a big deal. Furthermore, if you purchase a laptop with a backlit keyboard.  you can turn the feature on or off according to your needs.4.3  BrightnessOne of the main benefits of purchasing a laptop with a backlit keyboard  is the ability to use your system effectively in dimly lit environments. As a result, you should make sure that the backlit keyboard on your laptop is bright enough to meet your needs.4.4  RGBIf you're convinced that a backlit keyboard is a must-have feature for your ideal laptop, then go for the best that the market has to offer. When purchasing a laptop with a backlit keyboard, make sure that the keyboard can switch between different color ranges to effectively adapt to your surroundings.Ⅴ How Much does a Backlit Gaming Keyboard Cost?Gaming keyboards with backlighting are more expensive than standard keyboards, costing around $90 or more. They come in both wired and wireless versions. Wireless models require batteries to operate and may include a USB cable for charging the batteries by plugging the keyboard into the computer.Backlit gaming keyboards are made by a variety of companies, the most popular of which are Corsair, G.SKILL, Logitech, and RAZER.Ⅵ Frequently Asked Questions about Backlit Keyboard6.1 Are there wireless backlit keyboards?These keyboards are wireless and have backlit keys together. ... With backlit keys you are able to work in dark or dim light surroundings whereas wireless connectivity allows you to get free of all wires. Wireless keyboards mostly use bluetooth and are battery powered.6.2 Does backlit keyboard drain battery?Powering the keyboard backlights is a lesser drain on the battery, but there's a built-in setting that I recently learned about that turns off the keyboard backlights after a period of inactivity too.6.3 Does LED keyboard consume more power?There is no difference between the amount of energy/electricity usage a light up/LED keyboard will use compared to a non-light/non-LED up keyboard.6.4 Can you buy a backlit keyboard?Keyboards do come in a variety of different sizes, configurations, and builds, but these don't influence whether the keyboard has a backlight. Both membrane keyboards and mechanical keyboards may be built with backlights. Also, backlights are integrated into both desktop keyboards and laptop keyboards.6.5 Does Microsoft make a backlit keyboard?Yes, it does!all Surface Laptop 3 models come with the same three levels of the backlit keyboard. You can control the backlit on the Surface Laptop 3 keyboard by pressing the F1 media key (Next to Esc key). 1st Press: Activate backlight at level 1 (min). 2nd Press: Activate backlight at level 2 (medium).6.6 Does the surface laptop 2 have a backlit keyboard?Surface Laptop 2 keyboard and trackpadThe Surface Laptop 2 features a full-sized chicklet style keyboard with 1.5 mm of travel (versus 1.3 mm in Surface Pro 6) and three-stages of backlighting.6.7 Does HP laptop have backlit keyboard?Many HP laptops have backlit keyboards, some just a single color, others with what's known as RGB lighting, that can be customized to show different colors.6.8 Does ASUS have backlit keyboard?Here you can learn more about ASUS keyboard hotkeys introduction. For part of Notebook models, backlit function key is F3 and F4 key . If they are available, they can enable the backlit by pressing FN and F4 keys (FN+F4 keys) at the same time. ... For Gaming Notebook models, it's generally on Up and Down keys.6.9 How do I make my laptop keyboard glow?Also, depending on your computer model, your PC may be configured to control the backlit keyboard via the F9 or F11 button rather than the F5 button. Practice the same simultaneous Fn + F11 operation to turn on a backlight keyboard light.