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AC LED dimmer and dimming method thereby

  • US 8,324,823 B2
  • Filed: 09/04/2009
  • Issued: 12/04/2012
  • Est. Priority Date: 09/05/2008
  • Status: Active Grant
First Claim
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1. An alternating current (AC) light-emitting diode (LED) dimmer, comprising:

  • a rectifier to full-wave rectify a voltage from an AC voltage power source to generate a first full-wave rectified voltage;

    a voltage converter to generate a second full-wave rectified isolated voltage from the first full-wave rectified voltage, and to generate a pulse enable signal;

    a pulse width modulation controller to be supplied with the second full-wave rectified isolated voltage and to generate a pulse width modulation signal with the frequency of the pulse enable signal and with an adjustable duty-cycle ratio to dim an AC LED; and

    a switch to be controlled by the pulse width modulation signal to drive the AC LED by selectively providing the AC voltage to the AC LED.

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