Full Bridge Igbt Gate Driver

1. Ir Gate Drivers
2. Igbt Drive

This is my first post here, i need help on my final year project to make a grid connected inverter.For the full bridge inverter circuit i planned to use IRF2807 (75V Vds, 82A Ids) and Two IR2110 for the driver. I never use IR2110 before and failed many time when i want to make a H-Bridge for DC motor last year. Hopefully after asking you guys i can get enlightenment for my final year project.I planned to design the circuit based on this sample project that i get from another website:i have some question about the schematic since the specification is quiet different.My DC input voltage is 34V (2 series solar panel), The power rating is about 100Watt so the MOSFET should able to drain about 10A max current. The output of the inverter will be connected to 18V - 220V step up transformer. My controller will use hysteresis current control method so the switching frequency is not fixed and varied up to 100kHz. And i want to isolate (different ground) between my micro controller and power circuit. How can i use the optocoupler to isolate it?

Is there any optically isolated buffer since i planned to use buffer (micro controller (ATmega 8535, 16MHz - Buffer IC - Optocoupler - IR2110)Based on my specification, is there any component that i should change? I read before to change the diode to the fast recovery one, and change the resistor value.i will appreciate any suggestion or critics, thanks in advance. Hi there.If you have to isolate your ground, I would recommend you to use isolation transformerinstead of optocoupler. In this, you will no longer need to use high-side capable driver ICs,you will instead use a small gate drive transformer, buffered by the totem-poles.The transformer is very easy to wind, use small toroid core, about 10mmouter diameter or even slightly smaller. Make sure that it will not saturate.See the schematic below.Just make sure that you follow the polarities, you already know that of course.Feel free to ask if you have further questions. Hi there.If you have to isolate your ground, I would recommend you to use isolation transformerinstead of optocoupler.

In this, you will no longer need to use high-side capable driver ICs,you will instead use a small gate drive transformer, buffered by the totem-poles.The transformer is very easy to wind, use small toroid core, about 10mmouter diameter or even slightly smaller. Make sure that it will not saturate.See the schematic below.Just make sure that you follow the polarities, you already know that of course.Feel free to ask if you have further questions.Thanks for your answer ferdinand, may i know why you recommend me to use isolation transformer instead of optocoupler? Is there any problem that i will face if i use the optocoupler? Honestly your suggestion is quiet new for me, i never read this kind of gate driver. Since my deadline is less than 2 month i think i wouldn't try to gamble for trial and error. But i still curious about the winding ratio of the transformer and will it function well on the high frequency (up to 100kHz).But still i still prefer to use optoisolator for now, it's much simpler for me but i don't know what type of optoisolator that i should use and is there any other component that i need to use along with the optoisolator.Thanks. Using the transformer is much simpler in my opinion.If you can find a toroidal core, give me the part numberand I will provide you the number of turns including thecalculations.

100kHz is already high that's why I recommendedgate drive transformer.Don't worry, I already used this method of drivingmany times. It's easy to do if you have the materials.Less parts than the optocoupler and is also cheaper.Thx for your answer, but since this is my final year project i depend on my lecturer decision, and he said to use optocoupler for isolation. But i still don't know what type of optocoupler that could work in high bandwidth and pretty common so i could find it easily on my Country. Is there any suggestion for the optocoupler type? Hello all, last night i tried the IR2110 gate driver with IRF3205 MOSFET and make a half bridge circuit for testing. Here are the schematic for the test circuit:it goes well when i push on-off the Hin with a switch, the low side MOSFET is always ON so i connected the Lin directly to the 12V supply.

The DC motor could run when the switch ON for about 4 second if i keep push the Sw1 (until the boostrap capacitor run out). And if i periodically push and release the push button (to generate handmade PWM) the motor keep running.The problem come up when i want to control the PWM with my microcontroller (ATmega8535). The schematic are below:Still, the Lin is directly connected to vcc (5V) from microcontroller power suppy so it should always ON, and the Hin is connected to pwm signal generated by the microcontroller. When i power up the circuit the motor run slowly (much slower than before) but when i touch the Drain of the high side MOSFET with my finger and my foot is on the floor the motor runs as it should run, but when i pull up my feet from the floor the motor run slow again.

Then i realize i haven't connect the gnd from the microcontroller to power circuit GND. But when i connect the gnd (from uC) to GND (from power circuit), the motor totally shut down.i think the problem is in grounding or i confused how to use two different power supply to run the circuit.can you help me to see is there anything wrong from my circuit? Hi,The signal coming from AVR is at 5v level.

Connect pin 9 (VDD) to +5v instead of 12v. Then I think it should work fine. Change R1 and R2 from 220 ohm to 22 ohm or as I suggested before, anything between 10 ohm and 33 ohm. Also connect a 1k resistor from gate to source of the MOSFET.Hope this helps.Tahmid.Hello Tahmid, i forget to mention that i have tried it too before (connect the pin 9 to the 5V instead of 12V) but it didn't work. After read your reply and re-reading the datasheet i found this typical connection at the datasheet:and then i changed the circuit base on your reply and the typical connection into this:the circuit consist of 3 separate power supply:1.

Vcc (5V) & gnd from the uC board2. 7.4V Li-ion batt for the motor supply3.

12V from the power supplyit works just fine and i able to control the motor speed with PWM (5V) that generated from my microcontroller. And when i connect the 1k resistor between gate and source of each MOSFET, the motor run strangely. The motor seems to run and stop periodically even the PWM is on the high duty cycle.

When i disconnect the resistor the motor run normally.the most strange problem that i face now is when i disconnect all 3 power supply from the circuit and try to run it again, it just do nothing. The motor won't run until change the circuit with 12V on VDD, Lin, and Hin. After i do that (run the motor for a while) i able to control the motor with 5V vdd, 5V Lin, and PWM (5V) to the Hin. I have no idea what is going on, is it from the improper capacitor value? Hi,You have to use a fast switching diode at the bootstrap.

So, switch to 1N5818 as the first diagram shows. Try with this circuit, I think this should work:Hope this helps.Tahmid.- Post added at 12:19 - Previous post was at 12:17 -C1, C3 - 22uC2, C4 - 100nC5 - 100uR4, R5 - 22RThe rest of the resistors are in kilo-ohms.Hello Tahmid, thx for your response. Actually, i gave up trying with VDD 5v, so i decided to use vdd = 12V and convert my PWM level to 12V with hex buffer (use pull up resistor to 12V) and with those configuration i able to modulate the load supply voltage with PWM from my micro controller. I'm done testing with half bridge configuration in my breadboard and now i just started to build up the full bridge configuration in my breadboard. Hopefully it goes well, i follow the schematic from circuit project so there is no NOT gate in the circuit. I'm afraid there will be short period that both of my high and low MOSFET ON and get short circuited.

I don't know how to make the dead time between switching (hope you know what i mean) so i plan to use simple delayus or delayms function to make sure all the switches are in OFF state before proceed to the next cycle.btw, i have problem simulating my circuit in ISIS proteus, i didn't find IR2110 IC in the library. There's only IR2112 so i try to use it. Here's the schematic:do i have to change the hidden pins connection? I found that the VSS pin of the IR2112 connected to vcc in default.

It should connected to gnd right? But i tried both and the circuit still doesn't work.

Can you help me? And is there any way to get IR2110 in my library?

Hi,Not 100% sure, but I think, when using a high-low side driver, both high side and low side MOSFETs can not be on at the same time. So, that may be your problem as LIN is connected to VCC. I'm also not sure if Proteus simulates high-low side drivers properly. I'd suggest that you try the circuit practically on a bread board. I still suggest that you try the circuit I posted, once. When you have it working and you play with it, I'm sure many of your doubts and questions will be cleared and answered.Also, in the schematic, you didn't put any resistor between the AVR pins and the LEDs. Remember to add them.Hope this helps.Tahmid.

Hi,Not 100% sure, but I think, when using a high-low side driver, both high side and low side MOSFETs can not be on at the same time. So, that may be your problem as LIN is connected to VCC. I'm also not sure if Proteus simulates high-low side drivers properly.

I'd suggest that you try the circuit practically on a bread board. I still suggest that you try the circuit I posted, once. When you have it working and you play with it, I'm sure many of your doubts and questions will be cleared and answered.Also, in the schematic, you didn't put any resistor between the AVR pins and the LEDs. Remember to add them.Hope this helps.Tahmid.I tried to simulate with along try it on the breadboard. And yesterday i succeeded to invert 7.4V DC voltage into AC. Thanks for your help.The ATmega8535 generating PWM, breadboard circuit of Full Bridge InverterOutput of the inverter, still in low switching frequencyOutput of the inverter, trying high switching frequency up to 20kHznow currently i designing my PCB with altium for this project. Btw, i read in the datasheet that 1N5818 reverse voltage rating is only 30V.

I planned to use 36V DC voltage for my inverter. Do i need to change the diode? Is there other diode that have similar characteristic with 1N5818 but with higher reverse voltage rating?About the proteus, do you have any fullbridge inverter simulation file that i can modified to simulate my circuit? It don't have to use IR2110, maybe with some optocouplers for the gate driver? What is the voltage applied to the high side MOSFET?I suspect that the IR2110 might have been damaged.Check the diode D7 and capacitor C12 to see if they are okay.

What is the voltage rating of the capacitor you used?Where are the input signals to the IR2110 coming from? Can you post pictures of the waveform of the input signals. There might be cross-conduction between the MOSFETs.

What is the frequency of the input signals?I would replace R3 and R4 with 1k resistors but 4.7k is okay.Hope this helps.Tahmid.

VOL 46Implementing an Isolated Half-Bridge Gate DriverMany applications, ranging from isolated dc-to-dc power supply modules that call for high power density and efficiency, to solar inverters, where high isolation voltage and long-term reliability are critical, use isolated half-bridge gate drivers to control large amounts of power. This article will discuss details of these design concepts to illustrate the ability of isolated half-bridge gate driver ICs to provide high performance in a small package.A basic half-bridge driver with optocoupler isolation, shown in Figure 1, controls output power by driving the gates of high- and low-side N-channel MOSFETs (or IGBTs) with signals of opposite polarity. The drivers must have low output impedance, to reduce conduction losses, and fast switching—to reduce switching losses. For accuracy and efficiency, the high- and low-side drivers need very closely matched timing characteristics in order to reduce the dead time when one switch of the half bridge turns off before the second switch turns on. High-voltage half-bridge gate driver.As shown, a conventional approach to implementing this function uses an optocoupler for isolation, followed by a high-voltage gate-driver IC. A potential drawback of this circuit is that the single isolated input channel relies on the high-voltage driver circuit for the needed channel-to-channel timing match, as well as the required dead time. Another concern is that high-voltage gate drivers do not have galvanic isolation; instead, they rely on the IC’s junction isolation to separate the high-side drive voltage from the low-side drive voltage.

Parasitic inductance in the circuit can cause the output voltage, V S, to go below ground during a low-side switching event. When this happens, the high-side driver can latch up and become permanently damaged.

Optocoupler Gate DriverAnother approach, shown in Figure 2, avoids the problems of high-side to low-side interactions by using two optocouplers and two gate drivers to establish galvanic isolation between the outputs. The gate-driver circuit is often included in the same package as the optocoupler, so two separate optocoupler-gate-driver ICs are commonly required to complete the isolated half bridge—increasing the physical solution size. Note also that the optocouplers are manufactured separately, even if two are packaged together, limiting the ability to match the two channels. Allowing for this mismatch will increase the required dead time between switching one channel off and turning the other channel on, reducing efficiency. Dual optocoupler half-bridge gate driver.The optocoupler’s response speed is limited by the capacitance of the primary side light-emitting diode (LED); while driving the output to speeds up to 1 MHz, it will also be limited by its propagation delay (500 ns max) and slow rise and fall times (100 ns max).

To run an optocoupler near its maximum speed, the LED current must be increased to more than 10 mA, consuming more power and reducing the optocoupler’s lifetime and reliability—especially in the high-temperature environments common in solar inverter and power supply applications. Pulse Transformer Gate DriverNext, consider circuits where the galvanic isolation is provided by transformer coupling. Their lower propagation delays and more accurate timing can provide a speed advantage over optocouplers. In Figure 3, a pulse transformer is used; it can operate at the speeds often needed for half-bridge gate-driver applications (up to 1 MHz). A gate-driver IC can be used to deliver the high currents needed for charging the capacitive MOSFET gates. Here, the gate driver differentially drives the primary of the pulse transformer; the two secondary windings drive each gate of a half bridge.

In this application, pulse transformers have the advantage of not requiring isolated power supplies to drive the secondary side MOSFETs. Pulse transformer half-bridge gate driver.However, a problem can occur when large transient gate-drive currents flowing in the inductive coils cause ringing. This can switch the gate on and off when not intended, damaging the MOSFETs. Another limitation of pulse transformers is that they may not work well in applications that require signals with more than 50% duty cycle, as they can deliver only ac signals, and the core flux must be reset each half cycle to maintain a volt-second balance.

A final difficulty: the magnetic core and isolated windings of the pulse transformer require a relatively large package which, combined with the driver IC and other discrete components, creates a solution that may be too large for many high-density applications. Digital Isolator Gate DriverConsider now applying a digital isolator in an isolated half-bridge gate driver.

The digital isolator in Figure 4 uses a standard CMOS integrated-circuit process with metal layers to form transformer coils separated by polyimide insulation. This combination achieves more than 5 kV rms (1-minute rating) isolation, which can be used in robust isolated power supply and inverter applications. Digital isolator with transformer isolation.As shown in Figure 5, the digital isolator eliminates the LED used in an optocoupler—and its associated aging problems—consumes far less power, and is more reliable.

Galvanic isolation (dashed lines) is provided between input and output, and between the two outputs, eliminating high-side to low-side interactions. The output drivers feature a low output impedance to reduce the conduction losses—and a fast switching time to reduce the switching losses.

Digitally isolated 4-A gate driver.Unlike an optocoupler design, the high- and low-side digital isolators are manufactured on a single integrated circuit, with inherently matched outputs for better efficiency. Note that the high-voltage gate driver integrated circuit shown in Figure 1 has additional propagation delay in the level-shifting circuit, so it cannot match channel-to-channel timing characteristics as well as the digital isolator. Furthermore, integration of the gate drivers with isolation in a single IC package reduces the footprint of the solution to a minimum. Common-Mode Transient ImmunityIn many half-bridge gate-driver applications for high-voltage power supplies, very fast transients can occur across the switching elements.

In these applications, a rapidly changing voltage transient (high dV/dt) that capacitively couples across an isolation barrier can cause logic transition errors across the barrier. In an isolated half-bridge driver application, this could turn on both switches in a cross-conduction episode that could destroy the switches. Any parasitic capacitance across the isolation barrier tends to be a coupling path for common-mode transients.Optocouplers need to have very sensitive receivers to detect the small amount of light transmitted across their isolation barrier, and their outputs can be upset by large common-mode transients. The optocoupler sensitivity to common-mode transient voltages can be reduced by the addition of a shield between the LED and the receiver; a technique used in most optocoupler gate drivers. The shield can improve the common-mode transient immunity (CMTI) from a standard optocoupler rating of less than 10 kV/μs to as much as 25 kV/μs for an optocoupler gate driver. This rating may be suitable for many gate-driver applications, but CMTI of 50 kV/μs or more may be needed for power supplies with large transient voltages, and for solar inverter applications.Digital isolators can deliver higher signal levels to their receivers and withstand very high levels of common-mode transients without data errors.

Transformer-based isolators, as four-terminal differential devices, can provide low differential impedance to the signal and high common-mode impedance to the noise—which can result in excellent CMTI. On the other hand, digital isolators that use capacitive coupling to create a changing electric field and transmit data across the isolation barrier are two-terminal devices, so the noise and the signal share the same transmission path.

With a two-terminal device, the signal frequencies need to be well above the expected frequency of the noise so that the barrier capacitance presents low impedance to the signal and high impedance to the noise. When the common-mode noise level becomes large enough to overwhelm the signal, it can upset the data at the isolator output. An example of a capacitor-based isolator data upset is shown in Figure 6, where the output (Channel 4, green line) has glitched low for 6 ns during a common-mode transient of only 10 kV/μs. Capacitor-based digital isolator with CMTI of.

Brian KennedyBrian Kennedy is an applications engineer with the Digital Isolator Group at Analog Devices, Inc. He has been with ADI since April 2008 and is responsible for Gate Driver and Power Supply Digital Isolation Products. He has a Bachelor of Science in Electrical Engineering (BSEE) from State University of New York (Buffalo.)Related Products.3 kV rms Isolated Precision Half-Bridge Driver, 4 A Output.5 KV rms Isolated Precision Half-Bridge Driver, 4 A OutputRelated Categories.Related Markets & Technology. The cookies we use can be categorized as follows: Strictly Necessary Cookies: These are cookies that are required for the operation of analog.com or specific functionality offered. They either serve the sole purpose of carrying out network transmissions or are strictly necessary to provide an online service explicitly requested by you.

Ir Gate Drivers

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Igbt Drive

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