A High Conversion Ratio Matrix Auto-transformer Switched-Capacitor Converter for 48V Datacenter Application

This paper proposes a matrix auto-transformer switched-capacitor DC-DC converter (MASC) that converts 48-V to 3.2-V for datacenter applications. The proposed MASC is similar to the series capacitor buck with integrated inductors; however, it works at resonant mode to achieve ZVS switching. The operating principle and the power losses of the proposed circuit including both of the auto-transformer and semiconductor devices are analyzed. Compared with a switched-tank converter (STC) with the same conversion ratio, the power loss of semiconductor devices can be reduced by 68%. Furthermore, compared with a LLC converter with an isolated matrix transformer, the copper loss of the proposed matrix auto-transformer can be reduced by 50%. Finally, A hardware prototype has been designed and developed, both simulation and experimental results have been provided to demonstrate the feasibility and validity of the proposed circuit.