Digitally controlled driver for lighting fixture
First Claim
Patent Images
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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Abstract
The present disclosure relates to a lighting fixture that is capable of providing white light over an extended range of correlated color temperatures.
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Citations
30 Claims
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1. A lighting fixture comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A lighting fixture comprising:
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at least two LED strings, wherein each string of the at least two LED strings emits light; 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. - View Dependent Claims (27, 28, 29, 30)
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Specification