Patent ID: 8339067
Filing Date: 2012-12-25
Classification: H05B,Y02B

Abstract:
1. A controller controlling dimming of a light-emitting diode (LED) light source, said controller providing a pulse signal by comparing a sensing signal indicative of a current flowing through said LED light source to a reference signal, and said controller controlling said current through said LED light source according to said pulse signal during a first state of a pulse-width modulation signal and cutting off said current through said LED light source during a second state of said pulse-width modulation signal, said controller receiving a dimming request signal indicative of an operation of a power switch coupled between an AC power source and a bridge rectifier and controlling both a level of said reference signal and a duty cycle of said pulse-width modulation signal based on said dimming request signal, wherein said controller further comprises: a trigger monitoring unit receiving a monitoring signal indicative of a conductance status of said power switch, and identifying said operation of said power switch according to said monitoring signal.