Design and Analysis of Interleaved Boundary Conduction Mode (BCM) Buck PFC Converter

This paper presents design consideration and analysis for an interleaved boundary conduction mode power factor correction buck converter. A thorough analysis on the harmonic content of the AC line current is presented to examine the allowable voltage gain (K value) for meeting EN61000-3-2, Class D while maximizing the efficiency. Results of the harmonic analysis are used to derive the required value of K and therefore the output voltage necessary to meet class D requirements from a given AC line voltage. The discussed design consideration and harmonic current analysis are verified on a 300W, universal line experimental prototype converter with 80V output. The measured efficiencies remain above 96% down to 20% of full load. The input current harmonics also meet the IEC61000-3-2 (class D) standard.