A Dual-Inductor Quad-Path Hybrid Buck (2L4PHB) Converter With Reduced Inductor Current

Abstract

In high-efficiency 12-to-1–1.8-V applications, the small duty ratio ( ${D}~{\approx }~0.1$ ) and high voltage stress on power switches of the conventional buck converter bring significant efficiency penalty. This article proposes a dual-inductor quad-path hybrid buck (2L4PHB) converter that addresses these issues, achieving both high power conversion efficiency and power density. Compared to the widely used double step-down (DSD) converter, the proposed 2L4PHB converter reduces the average inductor current by 30% and the inductor current ripple by 18% at a voltage conversion ratio (VCR) of 0.15. In addition to continuous conduction mode (CCM), this design incorporates a discontinuous conduction mode (DCM) calibration loop to improve efficiency at light loads. The proposed 2L4PHB converter, fabricated in a 180-nm BCD process, achieves a maximum current density of 0.18 A/mm2 and 256 A/cm3 and a peak efficiency of 93.7% and maintains efficiencies above 85% across load currents ranging from 0.6 to 4 A, all while using a compact inductor with dimensions of $2.5 {\times } 2.0 {\times } 1.0$ mm3 and a DCR of 48 m $\Omega $ .