The pwm outputs of the microcontroller is capable of giving 16ma outputs and it is guaranteed with 220ohm resistor.Make sure you are putting at least 16mA into the opto LED's.
Strictly spoken, 16 mA output current won't be guaranteed by the specification of most uC port pins, even 10 mA is questionable. 2x16 mA would be clearly beyond rated currents. So an driver transistor is absolutely required for the parallel circuit but also advisable for the single output.my intention is to drive 2 optos with one uc pwm output. the 220ohm resistors should be parallel to each other.
You have to ensure the LEDs are getting about the same current, so you need to either drive them in series, or give each of them their own series resistor. Putting them directly in parallel with one series resistor is a bad idea.I didn't do that configuration yet but after solving this problem, my intention is to drive 2 optos with one uc pwm output. the 220ohm resistors should be parallel to each other. I mean leds should be parallel.
That's I was talking about....or give each of them their own series resistor.
Okay, I wasn't sure.That's I was talking about.
You want that trace to be as short and wide as possible. You want to keep the loop formed by the bootstrap capacitor, driver output, gate RD network, IGBT gate emitter, and driver ground return, as small as possible.I kept the ground connections of driver optocouplers with IGBT emmiters intentionally thin in order to decrease switching coupling.
Try for 15mm. I think it's doable even with big through hole components.and I tried to keep gate drivers as close to IGBTs as possible. The gate drivers are 30mm away from the IGBT's.
You want the TVS diodes to be as close as possible to what they need to protect (the IGBT gates, right?).Between them stands TVS diodes and gate drive resistors with schottky.
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