Heating Issue for a 415V SMPS.

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I have a 415V,50Hz SMPS using TOP264. I am facing heating issues with the SMPS. I have used a MOSFET in series with the internal MOS of the Top264. The Mosfet and the IC have severe heating problems. I have attached an image showing the part of the circuit having issues. It also shows the voltages at several points in that path. Can anyone point out some factors which may be causing this problem?

Hi techengg,

Have you measured the temperature of the device and the MOSFET? Can you send please?

It seems that the voltage rating of the AOT5N50 mosfet is only 600V, so the 582V is over the 90% derating factor

Regards,
PI-Pike