Hi Experts,
I make a reference design about two switch flyback with UCC28740. I tested the PCB but something went wrong. Could you pls tell me why Vcs is so large and how I can fix it. The waveforms are as follows.
1st channel: the vds of upper mosfet
2nd channel: the vds of lower mosfet
3rd channel: Vcs
4th channel:Vout
Regards,
Skylar