METHOD AND DRIVER FOR DETERMINING DRIVE VALUES FOR DRIVING A LIGHTING DEVICE
First Claim
1. Method for determining drive values for driving a lighting device at a desired brightness and color, said lighting device comprising of a plurality of light emitting diodes (LEDs) of at least two different colors, said method comprising the steps of:
- determining a first luminous flux weight ratio based on the desired color and a first drive current for driving each of the differently colored LEDs;
determining a first luminous flux for each of the differently colored LEDs based on the desired brightness and the first luminous flux weight ratio;
comparing, for each of the differently colored LEDs, the first luminous flux with a nominal luminous flux for a plurality of different drive currents;
selecting, for each of the differently colored LEDs, a preferred drive current that at least can produce the first luminous flux;
determining a second luminous flux weight ratio based on the desired color and the selected drive currents for each of the differently colored LEDs;
determining a second luminous flux for each of the differently colored LEDs based on the desired brightness and the second luminous flux weight ratio; and
determining a duty cycle for each of the differently colored LEDs at the selected drive currents, wherein the selected currents at the determined duty cycles produces the second luminous flux for each of the differently colored LEDs.
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Accused Products
Abstract
The present invention relates to a method for determining drive values for driving a lighting device at a desired brightness and color. The method comprising the steps of determining a first luminous flux weight ratio based on the desired color and a first drive current for driving each of the differently colored LEDs, determining a first luminous flux for each of the differently colored LEDs based on the desired brightness and the first luminous flux weight ratio, comparing, for each of the differently colored LEDs, the first luminous flux with a nominal luminous flux for a plurality of different drive currents, selecting, for each of the differently colored LEDs, a preferred drive current that at least can produce the first luminous flux, determining a second luminous flux weight ratio based on the desired color and the selected drive currents for each of the differently colored LEDs, determining a second luminous flux for each of the differently colored LEDs based on the desired brightness and the second luminous flux weight ratio, and determining a duty cycle for each of the differently colored LEDs at the selected drive currents, wherein the selected currents at the determined duty cycles produces the second luminous flux for each of the differently colored LEDs. The present invention provides for the possibility to limit the number of necessary computational steps for determining preferred drive currents. Furthermore, an increase in number of current level and/or differently colored LEDs would only slightly increase the computational cost.
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Citations
12 Claims
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1. Method for determining drive values for driving a lighting device at a desired brightness and color, said lighting device comprising of a plurality of light emitting diodes (LEDs) of at least two different colors, said method comprising the steps of:
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determining a first luminous flux weight ratio based on the desired color and a first drive current for driving each of the differently colored LEDs; determining a first luminous flux for each of the differently colored LEDs based on the desired brightness and the first luminous flux weight ratio; comparing, for each of the differently colored LEDs, the first luminous flux with a nominal luminous flux for a plurality of different drive currents; selecting, for each of the differently colored LEDs, a preferred drive current that at least can produce the first luminous flux; determining a second luminous flux weight ratio based on the desired color and the selected drive currents for each of the differently colored LEDs; determining a second luminous flux for each of the differently colored LEDs based on the desired brightness and the second luminous flux weight ratio; and determining a duty cycle for each of the differently colored LEDs at the selected drive currents, wherein the selected currents at the determined duty cycles produces the second luminous flux for each of the differently colored LEDs. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A driver for determining drive values for driving a lighting device at a desired brightness and color, said lighting device comprising of a plurality of light emitting diodes (LEDs) of at least two different colors, said driver comprising:
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means for determining a first luminous flux weight ratio based on the desired color and a first drive current for driving each of the differently colored LEDs; means for determining a first luminous flux for each of the differently colored LEDs based on the desired brightness and the first luminous flux weight ratio; means for comparing, for each of the differently colored LEDs, the first luminous flux with a nominal luminous flux for a plurality of different drive currents; means for selecting, for each of the differently colored LEDs, a preferred drive current that at least can produce the first luminous flux; means for determining a second luminous flux weight ratio based on the desired color and the selected drive currents for each of the differently colored LEDs; means for determining a second luminous flux for each of the differently colored LEDs based on the desired brightness and the second luminous flux weight ratio; and means for determining a duty cycle for each of the differently colored LEDs at the selected drive currents, wherein the selected currents at the determined duty cycles produces the second luminous flux for each of the differently colored LEDs. - View Dependent Claims (9, 10, 11, 12)
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Specification