I'm trying to make a 300V H Bridge for an electrostimulator. The circuitry is as posted here, using MOSFET P20NM60GP:
When I tested it with low voltage supply (just for the sake of safe testing), and a 15 Watts 1kOhm resistor I get the output waveform I desire, that is:
However, when I try to change the supply voltage to 300V (galvanically isolated, safety first!), with the same 15Watts, 1kOhm resistor I get this output:
I didn't take a picture of what that output looks like in 250us but the spikes shown in the image before were not square waves as the ones that showed up in low voltage. The ground for the Source of the low side MOSFETs is isolated from the one used in the IR2110 and the rest of the electronical devices (microcontroller, ICs, etc)
Any ideas as to why is this H Bridge misbehaving on High voltage? Thanks in advance!