A 1 kW eGaN FET-based LLC Resonant Converter in them 1/8th Power Brick Size for 48 V Server Applications

As high-performance computing and datacenters migrate power distribution design to 48 V onboard architecture, there have been ever-increasing demands on high-density and high-power 48 V bus converters. This paper presents the design of a 4:1 fixed ratio, 1 kW eGaN FET-based LLC resonant converter in the standard 1/8th power brick size for 48 V servers and racks. The high-density LLC resonant converter design will be introduced, detailing the component selection, transformer and resonant tank design, layout planning, start-up control strategy, and thermal design. The challenges in achieving such a high-density and high-current design are presented and addressed. The prototype of this standalone 1 kW LLC resonant converter achieves 1226 W/in(exp 3) power density, 97.6% peak efficiency and 96.4% full-load efficiency.