This reference design is an ultra-wide input, offline, high-side buck reference design that provides a 13V output at a maximum of 0.6A. The input voltage range is between 85VAC to 485VAC. The reference design uses the UCC28750 current-mode flyback controller without opto-coupler feedback. There is no isolation, the design uses a low cost current mirror to regulate the output. The design is developed to be resistant to magnetic fields up to 200mT near the inductor.