This schematics show the PWM driver stage of MC4X15A. IRF7862 is rated at 17-21A continuous current and pulses as high as 170A, but yesterday I took out two simply because I replaced IR2103 with IR2101 and did not realize that the later have no short-cut protection – so the MCU switched on both High and Low, dragging the PSU down. It was only ca 4A, but with no heat-sinks the SO8 packages will be exposed, so they snapped from overheating.
I planned on burning this board a bit, but not yet – I want to test if it works before I stress test it – lol. Well, new HEXFET’s – new try + I need to remove that IR2101S and get a IR2103S on.
Good news was that I could connect to 3.3V and things worked – it was only the HEXFET part that failed – no marks on the PCB or other Components.