Resonant switched-capacitors converters (ReSCCs) are becoming an attractive alternative to traditional buck converters in volume-constrained and high-conversion-ratio applications, thanks to their superior efficiency and power density. This work presents a new ReSCC topology derived from an interleaved ladder structure, which performs a nominal 4:1 down-conversion. A single semiperiod modulated quasi-resonant control strategy is adopted to achieve continuous regulation of the output voltage below the nominal level. A novel modular small-signal model of the converter is presented to verify the single in-band singularity of the proposed topology. To validate the proposed ReSCC topology and control, a prototype converter for 12 V down-conversion toward the 2.5 to 3 V range has been developed. The prototype features high-bandwidth closed-loop control, light-load operating mode, and switched soft-start. The use of PCB vias parasitic resonant inductors has allowed us to obtain a state-of-the-art power density of 0.53 W/mm2 at 5 A current load. The peak efficiency is 94.4%, while the efficiency at power density reaches 85.9%.
