TIDA-00129 Isolated PS Ref.Des.

A very good Reference Design from TI – Isolated Power Supply for PLC and Data Acquisition:
http://www.ti.com/tool/TIDA-00129
Based on a LM5017, a wide Vin Buck Regulator:
http://www.ti.com/product/lm5017
Datasheet:
http://www.ti.com/lit/gpn/lm5017