Thermal shutdown TOP257
Posted by: elmo2000
on
Our design made qith PI expert was failing on EMC. With the help of an EMC specialist the Transformer was optimesed but the new design overheads at room temperature. Our contact of PI in Germany, Munchen is unable to tell us why our design is overheating. So now we are stuck in our desing is there someone else I can contact on my design to get an review ?
Comments
I Compared VDS with the same supply voltage and load.
I don't have a current probe to monitor the current.
In the new design Rx = 9K76 in the old 14k7
Judging from vDS waveform it appears the new tranformer is very different design causing much higher RMS currents. I would go back to original transformer pirmary inductance, and turns and try to solve eMI some other way.
I would first compare drain current and VDS of TOPSwitch of original desing to your new design.