Step-Down DC-DC Converter Using Coupled-Inductors and Passive Clamped Circuit

A novel step-down DC-DC converter configuration is adopted in this paper. The new converter makes use the closed inversely coupled inductors topology. The proposed technique targeting the suppression of high content of switching noise that commonly accompanies the stepping-down converter circuits. This can be achieved by restraining the induced back electromotive force in the prime inductor. The induced back electromotive force is a result of discontinuous flow of line current in the prime inductor. The proposed technique preserves an uninterrupted stream of line current through-out the prime inductor which results in a considerable depression in the induced back electromotive force and consequently minimises the switching noise and enhancing the power conversion efficiency. A unique design of passive clamped circuit using coupled inductors is also proposed in this converter architecture. The leakage energies of the prime and the coupled-inductors can be recycled using the new passive clamped circuit and the captured energy can be then transferred to the load side alongside with the source or input energy. As a result, an efficiency improvement of the new converter can be achieved and the voltage stress on the power switches and diodes can be reduced. Circuit configuration, principles of operation and the transfer function of the new converter are figured out. The proposed concept of the new conversion technique is verified by the experimental and the simulated results of a range of case studies.