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Pulsed current averaging controller with amplitude modulation and time division multiplexing for arrays of independent pluralities of light emitting diodes

  • US 7,888,881 B2
  • Filed: 07/27/2006
  • Issued: 02/15/2011
  • Est. Priority Date: 07/28/2005
  • Status: Active Grant
First Claim
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1. A method for regulating current in an electrical load, the current provided to the electrical load via a switch and an inductor, the method comprising:

  • providing current to the inductor for a first predetermined period of time;

    following the first predetermined period of time, providing current to the electrical load and determining an average current provided to the electrical load during a second predetermined period of time;

    comparing the average current to a predetermined reference level;

    when the average current is less than the predetermined reference level, increasing the first predetermined period of time for a next cycle by at least one first predetermined time increment; and

    when the average current is greater than the predetermined reference level during the second predetermined period of time, determining a third period of time which elapses until the average current becomes less than the predetermined reference level, determining an integer corresponding to a ratio of the third period of time to the second predetermined period of time, and decreasing the first predetermined period of time for the next cycle by the integer multiple of the first predetermined time increment.

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