Universal Segmented Hysteresis Control Strategy for Multi-Ratio Resonant Switched-Capacitor Topologies

Poor voltage regulation capacity is a main limitation of resonant switched capacitor (ReSC) converter. To achieve voltage regulation, a universal segmented hysteresis control (SHC) strategy for ReSC converters with multiple voltage conversion ratios is proposed in this paper. Based on the inherent discrete voltage gain characteristics of this type of converters, this paper proposes applying a segmented hysteresis comparison logic in different gain ranges to achieve continuous voltage regulation and ensure zero current switching for high power conversion efficiency. The detailed operational principles and the output characteristics with SHC are analyzed. Moreover, as an example, the digital implementation of SHC in multi-ratio multi-resonance switched-capacitor converter is described and a prototype with 48 V input and 5-9.6 V (maximum 5 A) output is built and tested. The waveforms obtained from testing verify the correctness of the analysis and the dynamic performance, and the power conversion efficiency is measured with the peak efficiency of 96.7%.