A New ZVS Non-Isolated Full-Bridge Voltage Regulator Module with Gate Energy Recovery

Abstract

In this paper, a novel self-driven zero-voltage-switching (ZVS) non-isolated full bridge (FB) converter is presented for 12V input VRM application. Existing multiphase buck controller and buck driver can be directly used in the proposed converter. The advantages of the proposed converter are: 1) duty cycle extension; 2) significant switching losses reduction due to ZVS of all the control MOSFETs; 3) reduced reverse recovery loss and lower voltage rating synchronous rectifier (SR) MOSFET with lower RDS(on); 4) high drive voltage to reduce RDS(on) and the conduction losses of SRs due to gate energy recovery capability; 5) reduced body diode conduction and no external drive IC chips with dead time control needed for SRs due to the inherent current source gate drive circuit structure. The experimental results verify the principle of operation and significant efficiency improvement. At 12V input, 1.3V output and 1MHz switching frequency, the proposed VRM improves the efficiency from 80.7% using the buck converter to 83.6% at 50A, and from 77.9% using the buck converter to 80.5% at 60A.