I revisited this design for the bias supply of a new project I'm working on. I needed a 12V non-isolated output as well as a 12V isolated, and the input needs to work from 30-70V DC. Total power output is 12W with the primary (non-isolated) delivering 900mA and the secondary ('flybuck') about 100mA. AC noise is about 20mV on the primary and 50mV on the secondary.

This layout can be mounted vertically or horizontally and is pictured setup for vertical mounting.

It is slightly smaller than prior layouts and eliminates the bulky electrolytic input cap. It performs well across the entire operating regime with no loading quirks like I had observed with lower input-output voltage margins. Regulation on the primary is ~ 100mV. The secondary's regulation is +/- 300mV and does require about an 8mA load to keep the output from floating up to 20V.

The design workbook & KiCad files are posted in the files section.