Patent ID: 8710755

Claim:
A light emitting device driver circuit for driving a light emitting device circuit according to a rectified dimming signal, wherein the rectified dimming signal is generated from an AC input signal which passes through a tri-electrode AC switch (TRIAC) dimming circuit and a rectifier circuit, the light emitting device driver circuit comprising: a power stage circuit coupled between the rectifier circuit and the light emitting device circuit, the power stage circuit operating at least one power switch therein according to a switch control signal to generate a latching current for firing the TRIAC dimming circuit, wherein the latching current flows through the light emitting device circuit; and a light emitting device control circuit coupled to the power stage circuit, the light emitting device control circuit generating the switch control signal according to a detection signal; wherein the detection signal is generated according to the rectified dimming signal or a signal related to the rectified dimming signal, and the detection signal is generated when the rectified dimming signal changes from a neutral level to a predetermined level, and wherein the switch control signal turns ON the power switch continuously for a predetermined period.