Improved Light-Load Efficiency of Resonant Switched-Capacitor Converter

Resonant switched-capacitor converters (SCCs) are a sought-after candidate for high voltage and high power applications due to their advantageous features, including low electromagnetic interference, high-frequency operation, and compact size. Their ability to regulate output voltage despite significant variations in output load and input voltage stands as the main advantage of the SCC family. However, under light load conditions, structural efficiency decreases due to increased current stress and conduction losses. This not only affects converter efficiency but also reduces the lifetime and reliability of these topologies. To solve this challenge and achieve higher efficiency while minimizing current stress on structure devices under light load, this paper proposes a novel control method. This converter operation mode utilizes a single permanently active switch, while its complementary counterpart remains inactive. This configuration results in a reduction of inductor current, thereby enhancing the converter's long-term efficiency. Finally, the effectiveness of this method is validated through simulation comparisons with the conventional approach, demonstrating the high accuracy of the proposed control method. Furthermore, results show an improvement of more than 9% under light load conditions (10% maximum load).