An actual customer's application for a datacenter server power supply. The design had been completed using silicon carbide; reason being that silicon carbide is seen as a more mature technology and that the design has been under development for some time. They were still interested in seeing what sort of performance Transphorm’s GaN FET technology could provide in a bridgeless totem-pole PFC at a highline voltage of 180 V_AC with an output power of 4.2 kW. To determine this performance, Transphorm used a 4 kW, TDTTP4000W066 hard-switched bridgeless totem-pole operating at 66 kHz. Also, employing the latest 650 V/35 mΩ Gen III technology.