The TOPSwitchGaN™ family of ICs are highly integrated off-line switcher devices for power supplies in the range of 10 W to 300 W output. When operating with PCB cooling, devices within the TOPSwitchGaN family can deliver 300 W for universal input voltage range (85 VAC - 265 VAC), 400 W for high-line input (230 VAC), and up to 440 W when operating from a Power Factor Correction (PFC) input delivering 400 VDC. Applications include appliances, smart grid, and industrial power supplies and for power tools.

This application note is intended for engineers designing an isolated AC-DC flyback power supply or charger using the TOPSwitchGaN family of devices. It provides guidance which enables an engineer to quickly select key components and complete a suitable transformer design.