Hi,
....Actually......It turns out that the scope waveforms from above are probably correct...and that this 200W , 90-264VAC Flyback has been designed in very deep DCM.... for some unknown reason.....do you know why?
....The UCC28710 controller is said to be a Quasi Resonant controller, so its a mystery how they have got it to operate at the same frequency from 90-264VAC.
After some phorensic "digging", it looks like the attached is the schem and design calcs for this 200w flyback SMPS. (LTspice sim representation is also attached should you wish).
The biq question is...why have they done it like this?
They could so easily have used more turns on the secondary and got it to work in less discontinuos mode. As it is now, at max load, the primary peak current is fixed at 13.3A from 90-264VAC...and the secondary peak current is a whopping 33 Amps......all very needless. (it switches at 28700Hz)
The dissipation in the RCD clamp is going to be 7.9W, which they manage with twelve 1W, 2512 resistors in parallel.
They use a ETD39 core gapped to 1.17mm. The peak B is 0.31mT.
The transformer is made by Feryster and is part number TI-ETD39-26V-136W
The primary is split and uses just two parallel strands of 0.5mm TIW. There appears to be no "packing" to keep the primary away from the gap.....so you would actually assume that the Litz secondary is wound first on the bobbin.....but then why is the primary shown to be split...another mystery of this PM10816 design.
ti.com forum says that (concerning the RLTI-1131 transformer)....
RLTI-1131 was made by renco electronics. You can reach out to them using their contact page to get information on RLTI-1131
...however, searching for this on the web takes you to the Feryster transformer of part number TI-ETD39-26V-136W
I emailed Renco but obviously no reply yet.