5.5 kW Isolated 400 V to 50 V DC-DC Converter for Server Power Supplies

Inhalt:
The increasing power demand in data centers is driving the need for converters with higher power den-sity and efficiency. This paper presents a solution for the isolation stage in a sever-rack power supply, that complies with the Open Compute ORv3 specification [1]. The solution comprises four LLC convert-ers with stacked primaries and paralleled secondaries, between the 400 V input and 50 V output. It uses the same 150V-rated GaN transistors on both sides, and a simple planar transformer. Two transformer alternatives are presented to achieve highest peak efficiency (~98.5 %) or highest full load efficiency (~98 %). The converter can continuously process 5.5 kW and fits in a 80 x 70 x 27 mm volume, realizing a power density of 596 W/in3 (36.4 W/cm³.