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Digitally controlled driver for lighting fixture

  • US 9,723,680 B2
  • Filed: 05/30/2014
  • Issued: 08/01/2017
  • Est. Priority Date: 05/30/2014
  • Status: Active Grant
First Claim
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1. A lighting fixture comprising:

  • at least two LED strings wherein each string of the at least two LED strings emits light at a different color point;

    a driver module configured to;

    store a current model for each string wherein each current model effectively defines current as a function of Correlated Color Temperature (CCT) over a CCT range;

    determine a desired CCT;

    generate a current for each string based on the desired CCT using a corresponding current model, such that the light from each string mixes to form white light with a color point within a seven-step MacAdam ellipse of a black body locus at the desired CCT;

    select a reference control signal for each current based on the desired CCT;

    receive a tuning offset for each current model and adjust each current model based on a corresponding tuning offset, wherein the tuning offset is a multiplier applied to each reference control signal to adjust each current such that a CCT of light output by the lighting fixture matches the desired CCT;

    receive information indicative of a new CCT; and

    generate a new current for each string based on the new CCT using a corresponding current model, such that the light from each string mixes to form the white light with a color point that falls along the black body locus at the new CCT.

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