T14.7 - An Output Voltage Maximizer for Efficiency Improvement in Resonant Switched-Capacitor Converters

Resonant switched-capacitor (ReSC) converters have received growing interest due to their ability to achieve high power densities and efficiencies, particularly for fixed-ratio voltage conversion. While most existing control techniques focus on reducing either conduction or switching losses, their overall effectiveness across the full load range is limited since the relative distribution of these losses varies with converter parameters and operating conditions. This paper therefore proposes a feedback controller that leverages the output impedance characteristics of fixed-ratio ReSC converters to optimize their efficiency across a broader range of line and load profiles by sensing a single voltage node. The concept is validated on a 2-to-1 ReSC converter with experimental results demonstrating up to 91.3% loss reduction compared to conventional open-loop operation. With simplified sensing requirements and a fully digital implementation, the proposed approach offers a practical solution that can be extended to various ReSC topologies.