Resonant Switched-Capacitor Converter with Multi-Resonant Frequencies

This paper presents a new Multi Resonant Switched-Capacitor Converters (abbreviated as MRSCCs) for high efficiency and density non-isolated DC-DC application where large voltage step down ratios are needed. Derived from Resonant Switched-Capacitor Converter (RSCC), MRSCC employs two LC resonant tanks to partially replace the flying capacitors for energy transfer. During the dead-time in between two states of operation, second resonant tank recycles energy from the main resonant-tank allowing MRSCC to utilize conduction time effectively to deliver energy while becoming more resilience towards components variation, due to voltage coefficient and tolerance on Multi Layer Ceramic Capacitor (MLCC). These attributes of MRSCC make it a robust technology viable for industry's high-volume adoption. This paper presents the basic principle in 2 to 1 configuration to simplify the analysis of MRSCC and expands the concept for higher conversion ratio configuration (4 to 1). 2 to 1 and 4 to 1 MRSCC Hardware results are presented and compared to RSCC Hardware using the same power devices and PCB to provide objective comparison. Both comparison shows MRSCC to be superior over RSCC, and 4 to 1 hardware achieves 98.63% peak efficiency.