Test and verify that your overcurrent protection kicks in properly.
Measure switch node ringing (peak voltage) using high bandwidth (at least 100MHz?) oscilloscope with full load. Is it close to the MOSFET ratings?
Measure gate voltages with full load. Does it approach the limits, even for very short times? How much negative does it go? Some gate drivers die at slightly negative gate voltages, say, just -5V will kill some.
Overcurrent protection is OK, but we are not sure if in some "special cases" it can cause a problem.
Switch node voltage under normal operation is well below MOSFET rating.
Gate voltage goes to -1 V. The driver alowed voltage is down to -8 V.
I bet you are using one of those shitty level-shifting driver ICs that require a bootstrap charge pump for the upper MOSFET, aren't you? Those things are notoriously sensitive to high dV/dt leading to all sorts of mysterious failures at frustratingly random times.
Correct. We use a bootstrap capacitor to double the voltage to open the high side MOSFET. Is there some documentation regarding bootstrap and dV/dt problems?
Is this a specific "gate driver" built into the mcu designed to drive mosfets? or just a GPIO ?
Do you have TVS/Zener diodes between the gates and sources to prevent Vgs spikes from exceeding the max and damaging the mosfets?
It is a gate driver in the MCU. MCU is specialized in motor control aplication.
We do not have a zener to protect Vgs over/under voltage due to cost reasons. But we have a TVS input diode in the circuit, so an overvoltage to the MOSFETs is unlikely.
It's fine as long as the frequency is low and you have enough dead time.
Frequency is 13kHz and dead time is 400 ns. I think this is enough.