Sneak Circuit Analysis for n-stage Resonant Switched Capacitor Converters Based on Graph Theory

Sneak circuit is a latent circuit path or condition that causes undesired function to occur at some certain conditions. Sneak circuit phenomena were found in resonant switched capacitor (RSC) converters. However, because of the complexity of the n-stage RSC converters, the sneak circuit paths are difficult to find out. To solve this problem, graph theory is used to analyze the sneak circuit paths in this paper. Firstly, the n-stage RSC converter was simplified to a directed graph. Then connection matrix algorithm was used to find out all of the possible paths, and a virtual node was inserted to realize the calculation of loop paths. Next, path criterions were proposed to eliminate the false paths and identify whether the path was conventional or not. Finally, the validity of the proposed analysis method has been confirmed experimentally in the step-down RSC converters.