A Half Bridge Dual Frequency Buck Two Levels Of Vrm Research

Low voltage high current VRM is a computer CPU power supply of DC-DC modulepower,what is a hot and difficult field in power electronics sector. It has ever-increasingdemands for VRM as the development of the CPU. In order to further improve the powerdensity, it`s an inevitable trend for VRM that put the input bus voltage up to48V.The former two chapters begin by reviewing the course of development to VRM, theresearch status and challenges faced. It also explains the technical difficulties of the VRMdesign, combined with the VRM trends and performance requirements, proposed atwo-stage topology, suitable for48V input VRM. Then introduced several typical keytechnologies covered in this article, including synchronous rectification, interleavedparallel technology, integrated magnetic technology and so on.In chapter three, by thecomparison of several topologies selected the first satge is half-bridge doubler currenttopology,the second stage is low-frequency-interleaved double frequency Bucktopology.And then aim at double frequency Buck circuit`s control specificity determinedthe control strategy. The fourth chapter discusses the main circuit and control circuit`sparameters design. The fifth chapter combinate of system simulation and experiments andverified the theoretical analysis.This topic designed and producted a experimental prototype of48V DC input twostage converter. The first stage half-bridge double current topology works in the duty cycleof0.5open-loop state. To the second stage, high frequency part woks in doublepole-double zero voltage control, and low-frequency part woks in hysteresis control. Thisconverter has may advantages,such as simple controled, fast dynamic response, highefficiency, high power density. It has a wide range of application in low voltage highcurrent situations.