A New On-Time Adjustment Scheme for the Reduction of Input Current Distortion of Critical-Mode Power Factor Correction Boost Converters

摘要

A critical-mode (CRM) operation has recentlybeen used for low-to-medium power-level power factorcorrection (PFC) boost converter circuit. In theory, thiscircuit provides very good power factor and little distortion.However, in a real circuit, the input current of suchoperation suffers from significant input current distortion.In this paper, the phenomenon of input current distortionwas analyzed, and the cause was traced to the parasiticcapacitance of the MOSFET switch. An on-time adjustmentcontrol scheme, based on rigorous mathematical analysis,was proposed to overcome this problem. In addition, zerovoltage switching (ZVS) operation was Incorporated intothis new scheme. An implementation of the proposedstrategy was also presented. Simulations were conducted toverify,the validity of the proposed scheme.