Ultra-high Step-down Interleaved Converter with Low Semiconductor Voltage Stress

In this paper, interleaved technique along with components rearrangement are employed to enhance the coupled-inductor-buck converter in order to reduce the voltage across semiconductor elements. Similar to the coupled-inductor-buck converter, by selecting a proper turns ratio for the coupled inductors, low conversion ratio is achieved while extended operating duty cycle is achieved. Remarkably, the voltage stress of semiconductors is much lower than that of the coupled inductor buck converter. Also, the energy of the leakage inductors is absorbed and recycled. In this paper, operating principles, analysis and design procedure of the presented converter are discussed and confirmed by a 120W prototype converter.