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UCC28700 start up problem solved with 10pF on VS pin

Other Parts Discussed in Thread: UCC28700

Hello TI team,

I have building a fly back regulator with the UCC28700 few months ago.  With our first samples I had no problems. Now we have produced 60 items and now we have startup problems (starting again and again) with about 10 % of all. A small cap (10pF) at the VS pin solved this problem. My question is now: can I get any trouble with this small cab in the feature in relation to the  control behavior of the fly back?

The VS input resistor divider is 82.4k / 27k. I used the schematic of design example “PMP10344 - 85VAC-480VAC Input, 12V/25W Flyback”.

Thanks