Controlled-silicon adapting LED driving circuit, method and switch mode power supply

摘要

Disclosed are light-emitting diode (LED) driver circuits, methods, and a switch mode power supply. In one embodiment, an LED driver can include: (i) 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; (ii) a threshold voltage control circuit configured to receive a threshold voltage and an input voltage signal that represents the phase-loss half sine wave voltage signal, and to determine whether to output the threshold voltage based on angle information of the input voltage signal; (iii) a first control circuit configured to compare the input voltage signal against the threshold voltage output by the threshold voltage control circuit, and to generate a first control signal; and (iv) a power switch controllable by the first control signal to be off until an absolute value of the AC voltage is reduced to zero.

主权项

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.