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METHOD AND SYSTEM FOR DIMMING AC-POWERED LIGHT EMITTING DIODE (LED) LIGHTING SYSTEMS USING CONVENTIONAL INCANDESCENT DIMMERS

  • US 20090195168A1
  • Filed: 02/05/2009
  • Published: 08/06/2009
  • Est. Priority Date: 02/05/2008
  • Status: Active Grant
First Claim
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1. A dimming control circuit for dimming at least one light emitting diode responsive to an AC power signal from a dimming circuit, the control circuit comprising:

  • a power stage adapted to receive the AC power signal and coupled to each light emitting diode, the power stage operable responsive to first control signals to provide current to each light emitting diode;

    a current control loop circuit coupled to the power stage and operable to control the power stage to provide current to each of the light emitting diodes, the current having a value determined by a control value signal;

    an AC detector coupled to the power stage and operable to detect an instantaneous value of the AC power signal and to generate an AC presence signal indicating whether the AC power signal is present or absent; and

    a current control circuit operable responsive to the AC presence signal to generate the control value signal that is applied to the current control loop to control the current through each light emitting diode via the control value signal and achieve the desired dimming, and the current control circuit further operable to limit inrush current from the AC power signal.

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