In this circuit I designed, I use a TC4427 as driver and a dual package FDS8858CZ as MOSFET. I'm feeding the driver 12 V and the MOSFETs 18 V. I am using the C9, D3, and C10 and D4 components you see in the schematic to increase the applied PWM signal from 0-12 V to 6-18 V.
When I apply the signals you see in the schematic to run the motor in one direction, the P-channel MOSFET without PWM gets broken and the system becomes short-circuited.
I control the duty cyle with a potentiometer. When the duty cycle I apply is 0% (the motor is running at the highest speed) there is no problem. When I start it at 100% (the motor stops) and try to reduce the duty cycle with the potentiometer, the P-MOSFET without PWM is broken. When I feed the drivers and MOSFETs with the same voltage, there is no problem.
I think the problem is related to the C9, C10, D3, and D4 components I mentioned earlier, or the frequency. I tried to run the system between 1-10 kHz and I used different motors, but the result did not change. Can you help?