Design-Oriented Analysis and Performance Evaluation of Buck PFC Front-End

In universal-line ac/dc converters that require PFC, maintaining a high efficiency across the entire load range poses a major challenge. Typically, a boost PFC front-end exhibits 1-3% lower efficiency at 100-V line compared to that at 230-V line. It is shown in this paper that a buck PFC front end with an output voltage in the 80-V range can maintain a high-efficiency across the entire line range. A thorough analysis of the buck PFC converter operation and performance along with design optimization guidelines are presented. Experimental results obtained on a 90-W notebook adapter are provided.