Design of single stage PFC converter for LED power supply with low output twice line frequency ripple

A Single-Stage Power Factor Correction (S²PFC) converter is recently widely used as LED drivers for its cost-effective feature given bill of materials and relative high power efficiency compared to two-stage structure. Regarding to the respect of output twice-line frequency ripple, however, the S²PFC converter is more likely to reveal its weakness for the high ripple ratio in the output due to its simplicity in converter structure. This paper proposes a novel topology and ripple compensation control method which may effectively contributes to ripple reduction for the output twice line frequency ripple. The proposed circuit smoothes the power pulsation to the output end by using an extra switch and capacitor. Consequently the low frequency ripple will be significantly minimized. A satisfactory performance of the proposed method is confirmed by simulation.