High-Power Efficiency: GaN, SiC, and Si Boost Server PSU to 4.5kW

Navitas Semiconductor recently made waves in the tech industry by showcasing a groundbreaking 4.5kW 54V server power supply that leverages both Gallium Nitride (GaN) and Silicon Carbide (SiC) transistors. The company claimed a remarkable power density of over 130W/in3 coupled with an impressive efficiency rating exceeding 97%.

This innovative architecture marks a departure from the traditional four diode bridge typically found in server power supplies. Instead, Navitas opted for an active all-transistor circuit known as a multi-phase totem pole power factor corrector at the front end.

While commonly referred to as 'bridgeless' due to the elimination of the four diodes, this cutting-edge design actually incorporates a bridge of transistors. Specifically, two SiC mosfets in a half-bridge configuration switch at 80kHz, complemented by another pair of silicon mosfets operating at the mains line frequency. To ensure robustness, the SiC half-bridge and its inductor are duplicated in this multi-phase setup.

Following this initial stage is a 300kHz LLC converter full-bridge converter, featuring four GaN hemts in the driving bridge. Secondary-side synchronous rectification is managed by a silicon mosfet full-wave bridge, showcasing a seamless integration of different semiconductor technologies.

Looking ahead, Navitas Semiconductor has ambitious plans to unveil an even more powerful 8-10kW version of the server power supply by the end of 2024. The company expressed its commitment to leveraging the latest GaN and SiC advancements, along with innovative architectural enhancements, to further enhance performance and efficiency.