A sine-reference band (SRB)-controlled average current technique for a phase-cut dimmable AC-DC buck LED driver without an electrolytic capacitor

Abstract

A phase-cut dimmable AC-DC buck LED driver is presented with a sine-reference band (SRB)-controlled average current technique as a new control scheme. The proposed SRB-controlled average current technique can perform both sine current control and phase dimming control. The sine current control regulates the average LED current as a sine-wave maintaining high power factor. The phase dimming control removes visible flicker at AC line frequency without an electrolytic capacitor and makes the driver compatible with two types of phase-cut dimmer. Experimental results show line regulation <+/- 2.4% (90-260Vac), load regulation <+/- 0.7% (10-36 LEDs), PF > 0.95, and 90.7% peak efficiency.