Dear Team,
AC DC supply using UCC28740 we are facing issues during start up.
Power : 30 W
Output Voltage: 24 V (adjustable from 22 – 28 V)
Output Current: 1.3 A
Input Voltage: 90 – 264 VAC
As we are under NDA I need advice how to proceed with sharing more details. To give you some fist idea please find the attached scope plots.
VDD: magenta
VS: cyan
CS: green
We can see the part starts switching in special startup mode. At the 1.38V on VS pin when it should transition to normal operation mode there seems to be an issue and the part resets.
We can provide schematics and more details offline.
please advice!
Thanks Lutz
