A 36-to-60V Input Dual-Phase 2MHz 93%-Efficiency ZVT Series-Parallel Hybrid Buck Converter Using Single Auxiliary Inductor and Adaptive Time Multiplexing Control

Abstract— This paper presents a dual-phase series-parallel hybrid buck (SPHB) converter featuring a passive saving (PS) ZVT scheme and an adaptive time-multiplexing (ATM) controller. The aim is to intensify both power density and efficiency at light loads without reducing the switching frequency. With the PS-ZVT scheme, the converter can share the auxiliary inductor across two phases. Meanwhile, the ATM controller adjusts the peak auxiliary inductor current injected into switch nodes via the adaptive control of the interleaved auxiliary switches. Designed in a 0.5µm HV CMOS process, the proposed converter operates at a fixed 2MHz frequency, achieves over 85% efficiency across 0.2A-to-5A load, and has its power density improved by 1.6 times compared with the prior art.