Patent ID: 9055635
Filing Date: 2015-06-09
Classification: H05B,Y02B

Abstract:
1. A light-emitting diode (LED) driver, comprising: a) a silicon-controlled rectifier (SCR) and a rectifier bridge configured to receive an AC voltage, and to generate a phase-loss half sine wave voltage signal to a transformer for driving an LED load; b) a threshold voltage control circuit configured to receive a threshold voltage and an input voltage signal derived from said phase-loss half sine wave voltage signal, and to determine whether to output said threshold voltage based on angle information of said input voltage signal; c) a first control circuit configured to compare said input voltage signal against said threshold voltage output by said threshold voltage control circuit, and to generate a first control signal; and d) a power switch coupled to said transformer controllable by said first control signal to be off until an absolute value of said AC voltage is reduced to zero.