GaN Active-Clamp Flyback Converter with Resonant Operation Over a Wide Input Voltage Range

This paper presents an active-clamp Flyback converter with a resonant operation which can realize soft-switching on all power elements with the minimum of additional components compared to the classical hard-switched flyback topology. This converter is a good candidate for wide input voltage and load range application. The operational principle and design procedure are presented and verified experimentally with a 50W prototype converter at 1 MHz switching frequency, 18 to 80 V input voltage range and 15 V output voltage. In this switching frequency range, GaN transistors and planar transformer are used in order to improve the efficiency.