Optimized Trajectory Control for Soft Start-Up of Multiple-Mode Resonant Switched Capacitor Converter

Ensuring safe and rapid startup is paramount for improving the reliability of the resonant switched capacitor converter (ReSCC). This paper proposes a novel soft start-up strategy for a ReSCC with two-stage resonant tanks. The approach sequentially designs the state trajectories of both resonant tanks within the current-limiting band, followed by output voltage buildup through optimized switching frequency control. Rapid multi-stage capacitor voltage establishment is achieved while inrush currents and voltage spikes are effectively eliminated. The proposed strategy is elaborated in detail and its effectiveness is validated by experiments.