T06.1 - An Adaptive Zero Current Switching Control Technique for Multi-Resonant Switched-Capacitor Converters

By leveraging energy dense capacitors combined with efficient switch utilization, hybrid and resonant switched-capacitor (SC) converters have seen increased popularity due to their ability to achieve high efficiency and high power density. Multi-phase hybrid and resonant SC converters, here referring to topologies that operate with more than two equivalent circuit states, are especially attractive as they can achieve high conversion ratios with a fewer number of capacitors and switches than conventional two-phase hybrid and resonant SC converters. However, the complexity of these converters, coupled with circuit non-idealities, render the resonance timing during each phase challenging to estimate with precision. Here, we present an adaptive tuning control technique that can dynamically track the ZCS operation condition in order to achieve high performance, and facilitate larger scale adoption of these topologies. The concept was validated on a high-performance 48-to-6-V hardware prototype, where the proposed active control technique achieved nearly 20% reduction in power loss at the highest tested load (30 A) when compared with conventional open-loop control.