Patent ID: 8901851
Filing Date: 2014-12-02
Classification: H05B

Abstract:
1. A controller used in a LED driver, wherein the LED driver comprises a TRIAC dimmer configured to receive an AC input voltage and to generate an AC chopped voltage having a regulated conduction phase based on the AC input voltage, a rectifier configured to generate a DC chopped voltage in accordance with the AC chopped voltage, and a switching converter having at least one switch, wherein the switching converter converts the DC chopped voltage into a driving signal to drive a LED, the controller comprises: a dimming signal generator coupled to the TRIAC dimmer, wherein the dimming signal generator generates a dimming signal with regulated duty cycle in accordance with the AC chopped voltage; a dimming signal processor coupled to the dimming signal generator, wherein the dimming signal processor generates a processed dimming signal in accordance with the dimming signal, and wherein the duty cycle of the processed dimming signal is a sum of a predetermined duty cycle and the duty cycle of the dimming signal; and a switch control circuit coupled to the dimming signal processor, wherein based on the processed dimming signal and a feedback signal indicative of the current flowing through the LED, the switch control circuit generates a control signal to control the at least one switch of the switching converter.