Quote:
Originally Posted by jackbauer
Looks like the VLA is driving my gate off too fast. Common problem at my age i'm told  |
You put all of that effort into a fast, high current gate drive only to find that you need to slow it down.
What you want is a gate drive that operates at full gate current until the controlled voltage starts to rise, then drops to a low power mode. That way the device goes through the high power dissipation regime at maximum switching speed, but slows down at the end. Ideally you want to be just slightly under-damped (not critically damped) with a slight voltage bump.
I've seen discrete circuits that do this by shutting off the gate drive when the voltage starts to rise, using the propagation delay to match the remainder of the rise time. But I haven't see a gate driver IC that does this, or anything more sophisticated than "pulse mode".