A Comparative Study of Switched-Tank Converter and Cascaded Voltage Divider for 48-V Data Center Application

This paper presents a comparative study of the switched-tank converter (STC) and the cascaded voltage divider (CVD). The operating principles of the STC and the CVD with four times input-to-output conversion ratio ($4\times$ ) are discussed. Two design approaches of the CVD are considered, including the high-density CVD (CVD-HD) and the high-efficiency low-density CVD (CVD-LD). The power loss breakdown analysis and system efficiency evaluation are provided for both converters. From these results, it is found that the STC is more efficient and smaller in size than the CVD converter. Gallium nitride (GaN)-based hardware prototypes of both converters are built and tested. The $4\times $ -STC can achieve ~1500-W/in
³
power density and 98.79% efficiency. The $4\times $ -CVD-LD can achieve 1061-W/in
³
power density and 98.41% efficiency. Therefore, the $4\times $ -STC has 41% higher power density and 24% less power loss than the $4\times $ -CVD-LD.