I'm pulling my hairs out, trying to understand why the following circuit is burning MOSFETs.
I'm trying to build a simple AC switch that would have minimal losses. SI8751 provides galvanic separation from the uC that controls the circuit. T4 and T5 are 800V rated MOSFETs, theoretically protected by Transil (D10) with Vbr @400V. Theoretically, because after a few on-off cycles (probably depending on the timing on the mains) one of the MOSFETs always die. Switching cycle is very long, on the order of seconds.
My supply is 230V AC, I'm trying to key live wire for a small PSU (60W) that powers LED strip, so it's a bit hard to say, but definitely has significant capacitive / inductive load.
I would appreciate any input how to improve the circuit or at least pointers where to start the investigation.
Thanks!
I'm trying to build a simple AC switch that would have minimal losses. SI8751 provides galvanic separation from the uC that controls the circuit. T4 and T5 are 800V rated MOSFETs, theoretically protected by Transil (D10) with Vbr @400V. Theoretically, because after a few on-off cycles (probably depending on the timing on the mains) one of the MOSFETs always die. Switching cycle is very long, on the order of seconds.
My supply is 230V AC, I'm trying to key live wire for a small PSU (60W) that powers LED strip, so it's a bit hard to say, but definitely has significant capacitive / inductive load.
I would appreciate any input how to improve the circuit or at least pointers where to start the investigation.
Thanks!