We use ucc28951 to design a 2.2kW power supply. During the test, it was found that MOS would be burned all the time. Please help to confirm what is the reason and how to solve it?

Hello Jace

I had a look at your schematic and it all looks ok except that the burden resistor on the CT seems too high in value (51K) - I'd expect that it should be much, much lower (<50R) so please double check this.

There are many, many reasons why a PSU can fail so without waveforms it's not possible for me to say what might be causing the problem BUT it is possible to run the power stage from a very low voltage and once it's running ok from a low voltage you can steadily increase the voltage - checking waveforms as you increase the input voltage.

Here's a debug guide that shows how to do this - please follow it step by step and let me know how you get on.

/cfs-file/__key/communityserver-discussions-components-files/196/0447.UCC28950_2C00_-UCC28951-Debug.docx

Regards

Colin