4-Phase Floating Buck Converter Based on Series Capacitor Structure

The double step-down or also known as the series-capacitor (SC) converter, is attractive due to its high step-down conversion ratio and inherent current balancing. To have a higher step-down function and reduce the output current ripple, the multi-phase SC was proposed. However, as the number of phases is increased, the operation range of the converter is reduced by n (n is the number of phases). This paper proposes a 4-phase floating buck (4P-FB) converter based on SC structure to achieve a high conversion ratio while keeping the wide operation range. Moreover, the proposed converter has low input current ripple and natural current balancing for all four phases without feedback control. In this paper, a 1.25-kW 4P-FB converter is simulated to validate the performance of the proposed structure.