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Control circuit and method for controlling light emitting diodes

  • US 7,768,216 B2
  • Filed: 06/28/2006
  • Issued: 08/03/2010
  • Est. Priority Date: 06/28/2006
  • Status: Active Grant
First Claim
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1. A control circuit for controlling light emitting diodes, comprising:

  • a first switch to turn a first string of light emitting diodes on or off, the first switch comprising a control input;

    a first sigma delta modulator comprising;

    a signal input to receive a first control signal;

    a signal output electrically connected to the control input of the first switch; and

    a clock input to receive a clock signal having a clock period; and

    a first combiner circuit to generate the first control signal based on a data signal and a first noise signal;

    wherein the first noise signal comprises a signal having a time-averaged mean value equal to about zero.

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