Flicker‐free transformerless LED driving circuit based on quadratic buck PFC converter.

A flicker‐free transformerless light emitting diode (LED) driving circuit based on a quadratic buck power factor correction (PFC) converter is proposed. It combines a cascaded input buck PFC converter and an output buck dc–dc converter with a single switch. The proposed LED driving circuit can not only achieve high PFC to comply with the EN61000‐3‐2 standard and low output voltage without a high step‐down transformer, but also reduces second‐order line frequency current ripple flowing through the LED to eliminate light flicker of the LED. Experimental results of a 7 W prototype are presented to verify the analysis results of the proposed converter. [ABSTRACT FROM AUTHOR]