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when you say the low side switch, is it the low side switch on the same side of the highside IGBT or do you mean the lowside pair of the highside igbt?
Of course it can't. It would be so much easier to operate a single half bridge with an AC coupled load for test.how can the bootstrap capacitor of the left chip be charged in that case?
I just noticed the waveforms in post #14. They are simply unsuitable for a bootstrap driver.
I was mainly referring to the fact, that the low side driver has to be activated before the high side driver will ever work. But strictly spoken, we should ask, which hardware is drivem by the waveforn. If you refer to post #16, there won't be an output current, unless both are switched on simultaneously, apart from the bootstrap precharge problem.Can you please explain what is wrong with these PWM?
To understand about the available PWM option, we need to know the PIC type and connected output pins.we are getting our PWM from our pic microcontroller.
As said, you need an alternating activation of high- and lowside drivers to make the bootstrap circuit work. You have a 500 ms delay between both, the bootstrap capacitors won't keep charged for this long amount of time.the PWM that we still used was the one in the post #14
The PWM waveform isn't right. Why don't you refer to a Microchip PWM application note?we were expecting a continuous square wave output since if its already a full bridge...
Yes, it matters. Where did you get the 1k number? The datasheet is suggesting something like 10 ohm, if I remember right.Another question, does the resistance in the gate igbts matter? we are using 1kohms at the moment.
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