Other Parts Discussed in Thread: PMP8803
I'm testing the PMP8803 design and I'm finding I'm only getting an output of 7.8V under no load rather than 12V as per the design.
The only fix I've found is by reducing the Iled current. The design uses 4mA iLed with 2.5mA bias on the primary side - does this sound about right for a 80-160% CTR? I'm finding that reducing the Iled to around 2mA and the output restores to 12V.
There might be some other issue in my testing but I've not found it yet and the 4mA iLed looked quite high compared to other TI designs I've seen.