Thanks for the feedback.
I do use UCC28911 in several designs as a Flyback converter. The datasheet indicates that UCC28911 can be used as high-side buck but no information about the calculations. I also found several Ref. Designs but non of them provide…
Pan,
PMP9176 is probably a slightly better design to use - it's designed for 9 V @ 120 mA, and it uses UCC28910 (lower cost).
For universal AC input (90-264 V ac), the biggest challenge for 5 V output will be the small duty cycle at high line.
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Such a wide input range is challenging. Does the design need to be able to deliver full power 12 W even at min 19 Vdc input?
A DCM-only or variable freq valley-switching/QR controller will be challenged due to the very wide duty cycle range.
A fixed…