Resonant voltage divider with startup considered

In this paper, the resonant voltage divider (RVD) is presented with the fixed switching frequency over all the load range, which is to be used as the first stage of the bus converter. The proposed resonant voltage divider without any control loop embedded can reach very high efficiency from the light load to the rated load, especially for the light load. Above all, it has a serious drawback that a large surge current at startup causes components to be saturated or destroyed. Consequently, how to reduce such a surge current based on the proposed variable switching frequency at startup is also taken into account. The basic operating principles of the RVD and how to suppress the startup surge current are illustrated in detail along with some simulated and experimental results to verify its effectiveness.