A 48-to-12 V Cascaded Resonant Switched-Capacitor Converter Achieving 4068 W/in3 Power Density and 99.0% Peak Efficiency

A 4-to-1 cascaded resonant switched-capacitor (ReSC) converter, comprising two cascaded 2-to-1 ReSC converters, has been demonstrated to have high efficiency and high power density in previous literature. This work explores the approaches to further improve the performance of the cascaded ReSC converter, including merging two phases of the first stage into one phase and reducing the intermediate decoupling capacitor. The impact of the intermediate capacitor on the interaction between two stages is studied. With the optimization of circuit structure, active and passive component selection, layout, etc., this converter achieves a power density of 4068 W/in(3) under 48 V input and 60 A output. The converter also has high efficiency for the entire load range, achieving 99.0% peak efficiency and 97.9% full-load efficiency with gate drive loss included. Both power density and efficiency are superior to the state-of-the-art.