48 V-12 V Isolated-type DC/DC converter miniaturized using GaN transistors and operating at 2-MHz switching frequency Koki Sakamoto Atsushi Yamaguchi Ken Nakahara

Abstract

The compatibility of high switching-frequency $(f_{sw})$ and high efficiency is achieved using GaN transistors in 48 V-12 V isolation-type DC/DC converter. High fsw increases power loss, but generate a downward trend for the required magnetic flux per switch. Hence, an optimal fsw is found for gaining the compatibility. The prior-to-experiment loss estimation proves that $f_{sw}\sim 2$ MHz is optimal, and a converter with the size of 25.0 mm $\times$16.8 mm $\times$ 4.5 mm is made assuming that GaN-FETs are employed. With an air-cooled condition of 2m/s, this converter can transfer 129 W output power and its maximum power conversion efficiency reach to 95.3%.