Picture: input from 160V ->350V/2s->160V; output is 160V->200V/2S->160V; （because the input range of the latter power module is 100V to 200V）
ISSUE: when input was 350V,and output is 200V,the MOS is worked in variable resistance region。NOW， the Vdg is 138V， Will MOS be broken down?
I think the mos will be broken down, so what better circut do you have to withstand 350V/2S?
Hi ,Mosfet failure will depend on power dissipated in this duration. If the current is large for these 2 sec then the FET will fail with 150V Vds.In your application , with 4A load , the FET will fail.
Can you elaborate what is the end application where you expect this 150V surge to last for 2 sec. Automotive surges typically last few msec.