Abstract：In the conventional Buck converter with synchronous rectifier, hard-switching operation of the main switch and reverse-recovery problem of the synchronous switch result in deteriorated switching loss and electro magnetic interference (EMI) problem. In order to avoid these two undesired shortcomings, a novel synchronous Buck converter with a coupled inductor was proposed to achieve zero-voltage-switching for both switches over the whole load range. The converter is simple since only a coupled winding and an auxiliary diode are needed. In the paper, the operation principle and steady characteristics of the converter were thoroughly analyzed. Moreover, variable frequency modulation was employed to reduce conduction losses and thus improve converter efficiency. Finally, design considerations were given and experimental results were provided to verify the advantage of converter and the correctness of theoretical analysis.
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2016, Vol. 31 
