Invention Grant
US08928241B2 Method and apparatus for controlling brightness of light emitting diodes 有权
用于控制发光二极管亮度的方法和装置

Method and apparatus for controlling brightness of light emitting diodes
Abstract:
A circuit for driving a light emitting diode (LED) comprises: an alternating voltage power supply, comprising a triac dimmer having a firing angle and output terminals that provide power to the LED; a zero crossing detector that detects a polarity change of the alternating voltage provided by the alternating voltage power supply and provides a zero crossing output signal indicative of the zero crossing; a timer triggered by the zero crossing output signal that generates a timer output signal during a time period of the timer; and LED power circuitry that reduces current to the light emitting diode based upon timing characteristics of the timer output signal.
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