A Multiphase Structure Applied in VRs for Portable Applications

Abstract

Nowadays, portable applications are very important in telecommunications, business and entertainment markets. Handheld devices like Ultra Mobile PCs, cell phones, PDAs and Mobile Internet Devices are battery-dependant. Synchronous buck converter (SBC) is extensively used as voltage regulator (VR) in mobile devices; however, at very light-load operation, the converter efficiency is severely reduced. That condition is normal in these converters, but in battery operated systems, it becomes critical. In this paper, a VR converter, which is based on a multiphase structure, is presented. Proposed converter has three load-dependant operation modes and MOSFET parameter optimization is used. A study about the influence of the discontinuity period in discontinuous conduction mode operation and some efficiency-based comparisons among operation modes are presented; besides, the basic concept as well as the analysis and simulation of the proposed VR are presented.