Hello T.I Community...!!!
I'm a test engineer (not design engineer) and my problem is that We are having a lot of failures on Our power supplies that use the chip UCC28061D during Start Up test. The switcher transistors are damaged. And I want to know tips or suggestions to check or looking for the root cause. I observed that at start up some cycles the phases on both transistors are the same, and after some time the chip make the correction and the driver signals are 180° out of phase. The input voltage at Start Up test is 90VAC and the Output voltage is loaded at 500W, this is in one of Our test equipment, but in the other the input voltage at start up is 120VAC and the output is loaded at 0W or Not load. Looks like We have the problem at different load condition. Somebody can help to provide a guide or Steps to verifiy...signals..??
What is the safe time for this topology to start working properly this PFC stage 200mS, 400mS or less...?
Thanks and Regards.....