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LED DRIVER WITH END-OF-LIFE DETECTION CIRCUITRY

  • US 20120187847A1
  • Filed: 12/20/2011
  • Published: 07/26/2012
  • Est. Priority Date: 12/20/2010
  • Status: Active Grant
First Claim
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1. An LED lighting device comprising:

  • a DC/DC power converter having first and second converter output terminals and effective to supply an output voltage across the converter output terminals;

    first and second lighting device output terminals coupled to the first and second converter output terminals, respectively, and effective to receive an LED lamp;

    a current sensor coupled between one of the converter output terminals and a corresponding device output terminal, and effective to detect an output current;

    a voltage sensor coupled across the converter output terminals and effective to detect the output voltage; and

    a control circuit effectiveto control the DC/DC power converter to adjust the output voltage based on the output current detected by the current sensor with respect to a target value,to compare the output voltage detected by the voltage sensor to a predetermined upper limit value, and upon the output voltage exceeding the predetermined upper limit value, to disable the DC/DC power converter,to measure an accumulated lighting time of the device, andafter the accumulated lighting time has exceeded a predetermined switching time, to decrease the upper limit value as the accumulated lighting time passes.

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