JohnWondersWhy
New Member
Hello,
I've seem to be able to kill every mosfet I try when I use a bus voltage > 50v.
I attached my circuit, all real basic stuff, just like the data sheets recommend. The circuit works great below 50 volts. But above that, both mosfets will die, even at near zero motor amperage.
I've scoped everything out . . . all the voltage readings at the mosfets are in range.
Everything on the driver is in range except at bus voltages >45, I get a negative voltage spike between Ho and COM at the end of a pulse. At 50v the spike is -10v, at 100v the spike is -20v. Again, that's when I measure relative to COM.
Taking readings at the mosfet between g-d-s, everything looks clean and crisp, no overshoots. Seems like the driver ought to be the component that fails. In desperation, I've been poking around with different caps, resisitors, diodes, big and small mosfets, and adding parts randomly. Something is seriously wrong . . .
This is nuts. Any ideas of what I can try?
I've seem to be able to kill every mosfet I try when I use a bus voltage > 50v.
I attached my circuit, all real basic stuff, just like the data sheets recommend. The circuit works great below 50 volts. But above that, both mosfets will die, even at near zero motor amperage.
I've scoped everything out . . . all the voltage readings at the mosfets are in range.
Everything on the driver is in range except at bus voltages >45, I get a negative voltage spike between Ho and COM at the end of a pulse. At 50v the spike is -10v, at 100v the spike is -20v. Again, that's when I measure relative to COM.
Taking readings at the mosfet between g-d-s, everything looks clean and crisp, no overshoots. Seems like the driver ought to be the component that fails. In desperation, I've been poking around with different caps, resisitors, diodes, big and small mosfets, and adding parts randomly. Something is seriously wrong . . .
This is nuts. Any ideas of what I can try?