I'm trying to build a sensors motor controller for a 500 watt bicycle hub motor. The problem I am having with it is when I connect power (4500 mAh 12s lipo) I usually destroy a transistor or two immediately.
At first, I figured the problem was too much current in the MOSFETs so I got bigger ones capable of 120 amps, 480 amps pulse (much more than the battery can even do) and it still broke the transistors, although not quite as loudly.
Next I figured that timing could be the problem, so I left the MCU disconnected when I applied Vcc - issue still occurred.
I then added pull-up/pull-down resistors on the bridge to make sure they weren't in some kind of floating phase - issue remained.
I also tried hooking up things in a variety of orders such as with/without the motor, with/without the MCU, but I still get the same problem.
Let me clarify a few things about the schematic:
High side are P-channel, low side are N-channel, 100k resistors on the pull-up/pull-down, schmidt trigger mainly to invert signal to P-channel so they are active high from MCU (ATmega328). No gate resistors (from what I read this only slows down switching which could make matters worse).
I really am lost as to what the problem could be here. I still haven't tried putting pull-up/pull-down resistors on the drivers or messing with the code too much, because I figure the code doesn't have much to do with it at this point since the issue occurs without hooking up motor or MCU. I wanted to stop for a minute and see if I'm missing something obvious before I go on, because I feel like I'm just rapid firing trivial changes at this point.