Low Output Current Ripple Ultra High Step-Down Two-Phase Buck Converter With Low Switching Losses

This article introduces a new two-switch step-down dc–dc converter. By integrating Valley-Fill circuit with coupled inductors, and using the cross-coupled inductor technique, the proposed converter achieves a substantial reduction in the output current ripple. This configuration not only improves the voltage gain of the converter but also alleviates voltage stress on diodes. Employing dual magnetic elements provides the realization of a dual-phase buck mechanism, enhancing converter efficiency. Moreover, the converter demonstrates ripple cancellation capabilities. One switch in the proposed converter turns on under zero current switching conditions, while the other incurs minimal switching losses due to its low drain-source voltage, which reduces both switching losses and the capacitive turn-on loss. Detailed analysis and design guidelines are presented to validate the performance of the proposed converter. Experimental validation is provided through a 300 to 24 V 120 W prototype converter, which affirms the circuit’s operational integrity and theoretical analysis.