A new bleeder circuit for TRIAC dimmable LED driver based on single-stage topology with a capacitor input rectifier

Abstract

A TRIAC (TRIode for Alternating Current switch) dimmable LED (Light Emitting Diode) driver based on the single-stage topology using a capacitor input rectifier provides many advantages such as small-scale implementation and low output current ripple. This circuit topology, however, has a problem: a large inrush current to the smoothing capacitor. To reduce the inrush current, this paper focuses on the bleeder circuit in the LED driver. This paper analyzes the relationship between the inrush current and the bleeder circuit operation and proposes a new bleeder circuit for reducing the inrush current. Experimental results demonstrate advantages of the proposed method, including inrush current reduction. The proposed method achieves further small-scale implementation and low electromagnetic noise for the intended circuit topology.