A Coupled Inductor High Step-Down Voltage Regulator Module With Zero Current Soft-Switching

This article presents a detailed analysis and design of a coupled inductor high step-down converter for 48 V-bus data centers. The proposed converter maintains the simplicity and low component count of conventional converters while extending the duty cycle and enabling soft-switching conditions for the mosfets. The proposed adaptive frequency control method adjusts the switching frequency proportionally to the output current to achieve zero current switching at light loads, where voltage regulator modules (VRMs) operate the majority of the time. This frequency control method is compatible with state-of-the-art VRM controllers with adaptive on-time features. Furthermore, this converter is adaptable to interleaved structures with phase-shedding capability, enhancing transient performance and power density. Finally, this article presents the steady-state analysis and experimental results of a 24 W prototype.