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Help protecting NFET switching inductive load

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pigman

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Hi,
I have a N FET switching a transformer with the attached circuit design. This is switched at high frequency from a MCU at logic level. I recently did some testing and if I "bounce" the input power somehow the FET eventually fails and goes almost fully on and cooks itself. Is there something I could be doing here to prevent that? Would a 20k ohm across the gate and source help?

Thanks in Advanced!
 

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The problem is what the Drain is connected to; nothing done at the Gate will fix that.
 
so the only way would be physically disconnecting the drain from the circuit until its stable? IE a relay or something? The circuit is protected by 36V 1500W Bidirectional TVS Diodes and the TVS next to the FET is the same.

What is normally done in these types of circuits?
 
What do you mean "bounce" the input power? :confused:

You may have to use a higher voltage rated MOSFET.
 
I can cause the fault by taping the power on and off a bunch of times, like on/off each second, after a bunch of times one of the fets will go on and that will create a short which cooks it.
 
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