A family of buck-type DC-DC converters with autotransformers

This paper introduces a family of buck-type DC-DC converters with autotransformers, including forward, push-pull, half-bridge, and full-bridge topologies. Compared with an isolated transformer, the autotransformer has a simpler winding structure, and it only needs to transfer part of the input power, resulting in a smaller secondary winding current. Analysis shows that the autotransformer can also help to reduce the voltage stress and current ratings of power devices in the DC-DC converters. For some applications, a simple lossless passive clamp circuit can be implemented to solve the transformer leakage problems, and the gate drive is significantly improved with a simple self-adaptive dead-time-controlled bootstrap gate driver. Simulation and experimental results show that the proposed topologies are very suitable for high-frequency applications.