A Time-Based Integrated Three-Level Buck Converter with Enhanced Flying Capacitor Balancing Feedback Loop

Flying capacitor multi-level (FCML) converters offer high efficiency but pose challenges with flying capacitor balancing, particularly under light load conditions. Improper balancing increases switch voltage stress, negatively affecting performance and device longevity. In this paper, a time-based dual-loop control method is introduced for a 10MHz three-level buck converter (TLBC), integrating flying capacitor and output voltage regulation into a unique structure. Compared with previous work, the dual-loop control directly addresses the light load balancing issues already mentioned, ensuring adaptive regulation across the full load range. Simulation in SIMetrix/SIMPLIS environment results and theoretical analysis demonstrate the effectiveness of this technique, enhancing the performance of time-based control in dynamic response in portable systems. The controller was designed in a 180-nm BCD technology. Index Terms-DCDC converter, time-based control, three-level buck converter.