A simple and effective method to alleviate the rectifier reverse-recovery problem in continuous-current-mode boost converters

Rectifier reverse-recovery problems cause a significant efficiency reduction as well as severe electromagnetic interference (EMI) in continuous-current-mode (CCM) boost converters. To alleviate these problems, this paper presents a simple and effective solution that involves shifting the original rectifier current to a new branch, which consists of a rectifier and a coupled winding of the boost inductor. When the active switch turns on, the current through the original boost rectifier is zero and the current decrease rate di/dt in the new branch is controlled by the leakage inductor. Based on the operation analysis, design issues to guarantee complete current shift are also addressed. Applying the proposed concept to a 500 W CCM DC/DC boost converter and a 500 W CCM power factor correction (PFC) boost converter with universal-line input generates a 2% efficiency improvement. The same concept can be easily extended to other basic DC/DC and CCM PFC converters.