Other Parts Discussed in Thread: UCC28C43, UCC2805
We were looking to replace UCC28C43 with UCC280x since it can operate at lower VIN in a flyback.
We dropped in the 2803 which we didnt' realize a 100% max duty cycle and adjusted the feedback loop slightly in order to meet target , however we notice that this part will not startup anymore and upon startup the duty cycle gets pegged at 100%.
I am aware that flyback Dmax should be limited to 50% for typical design without efficiency techniques.
Basically when we dropped it in we noticed that at startup the duty cycle gets pegged at 100% and the power fet heats up. Since this design was already working with 28C43 we are fairly confident it is close to what we need for 2803,
My thought is that a potential issue is that the startup behavior of 2803 might be problematic for our design since it has dmax of 100% which it attemps at startup. Can you comment if this could potentially cause an issue that you may have seen before?
Should we try UCC2805 instead?
Best regards,
Brian Crutcher
