High-efficiency, High-density Isolated/Regulated 48V Bus Converter with a Novel Planar Magnetic Structure

In this paper, an LLC converter utilizing gallium nitride (GaN) transistors is proposed for a 48V regulated and isolated bus converter. Compared to pulse width modulation (PWM) based topologies, the soft switching capability of an LLC allows operation at very high frequencies. In addition, the magnetic components size is reduced without sacrificing efficiency. A novel magnetic structure that integrates a matrix transformer and inductor with the same winding and magnetic core is proposed in this work, to allow a high-density and high-efficiency LLC converter design for a bus converter. A 40V-60V input and regulated 12V output converter is developed to deliver a 1 KW output power in a quarter brick form factor. The designed converter can achieve a power density of 700 W/in
³
with a maximum efficiency of 97.82% at half load, dropping to 97.7% at full load operation.