1200v IGBT project help.


Thread Starter



I'm wanting to pulse 900v dc through an IGBT. I've got an optocoupler that controls a 15V pulse to the gate. I'm having trouble seeing a signal past the emitter as nothing is getting through.

Your feedback is appreciated. Thanks.


You should use a Darlington pair on the IGBT base. The optocoupler won't have the power to force it on.

Maybe you have a better circuit to use? The load should be on the collector side?
That circuit could blow up!!!!!!!!!!!!!!!!

At 4,000 ohms on the device's emitter output, it's going to drive the whole 15-volt control system up to 900 volts when it tries to turn on.

The 4,000-ohm load should be on the top collector side plus for a larger sized IGBT intended to work at high switching speeds a proper dedicated driver circuit. Or you could always use and IC.
Hi again.

Thank you for the info. It was most helpful.

I want to keep the optocoupler for isolation. The regulated 15V input does have over-voltage protection in case of a fault. Would it be best for the load to be before the IGBT?

I have seen IGBT configurations with the high resistance loads on the emitter though. Don't worry, I'm using lower voltages to experiment and I will not blow myself and the circuit UP!