I am designing a class D audio amplifier using an HIP4080A integrated circuit to drive an H-bridge, simulating in Proteus. My problem is that the output pins of the integrated circuit, although rated for 2A or so, only supply 300mA (peak) into the gates of my power MOSFETs (this happens for both high and low side devices). Consequently, the transistors turn on very slowly and I get some really bad shoot through (500A for 100ns).
Things I tried:
- Changing the gate resistors - current peaks at 300mA below 12 ohms
- Lowering the frequency of my PWM signal
- Ditching my PWM signal and using separate test sources at 600, 100 and 50 kHz, 50% duty
- Modifying the bootstrap capacitors
- A whole bunch of different MOSFETs
- Supplying the IC with a higher voltage
- Increasing the dead time via the HDEL and LDEL resistors
- Lowering the high voltage supply from 75 to 50 V
Maybe this is just a glitch in the software?
VBAT is 12 and HV is 75 volts. The shortest pulses from the PWM signal are ~80 ns (the IC needs at least 50).
Any help would be much appreciated!