Lighting system having a dimming color simulating an incandescent light
First Claim
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1. A method of operating a Light-Emitting Diode (LED) light, comprising:
- supplying a current to a light source, the light source having first and second groups of light-emitting diodes (LEDs) and each group having at least one LED;
generating a timing signal having a period;
supplying the current to the light source at first current level;
a controller sensing the first current level;
in response to the first current level, the controller alternately pulsing the first and second groups of LEDs during the period, such that the first group of LEDs has a first duly cycle and the second group of LEDs has a second duty cycle during the period;
supplying the current to the light source at a second current level different than the first current level;
the controller sensing the second current level;
in response to the second current level, the controller alternately pulsing the first and second groups of LEDs during the period, such that the first group of LEDs has a third duly cycle different than the first duty cycle and the second group of LEDs has a fourth duty cycle different than the second duty cycle during the period; and
a change in the duty cycle of the first group of LEDs from the first duty cycle to the third duty cycle being inverse to a change in the duty cycle of the second group of LEDs from the second duty cycle to the fourth duty cycle.
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Abstract
A lighting system has a white light source and a color light source, a control circuit pulses the white and color light sources and changes relative duty cycles of the light sources to alter a color output of the lighting fixture, in response to a change in a control signal from a controller. A comparator compares a reference voltage relating to an aggregate current driving the light sources to a signal voltage relating to the periodic signal from a signal generator. The comparator controls a switch that controls one of the light sources. A duty cycle of the color light source varies inversely to a duty cycle of the white light source.
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Citations
29 Claims
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1. A method of operating a Light-Emitting Diode (LED) light, comprising:
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supplying a current to a light source, the light source having first and second groups of light-emitting diodes (LEDs) and each group having at least one LED; generating a timing signal having a period; supplying the current to the light source at first current level; a controller sensing the first current level; in response to the first current level, the controller alternately pulsing the first and second groups of LEDs during the period, such that the first group of LEDs has a first duly cycle and the second group of LEDs has a second duty cycle during the period; supplying the current to the light source at a second current level different than the first current level; the controller sensing the second current level; in response to the second current level, the controller alternately pulsing the first and second groups of LEDs during the period, such that the first group of LEDs has a third duly cycle different than the first duty cycle and the second group of LEDs has a fourth duty cycle different than the second duty cycle during the period; and a change in the duty cycle of the first group of LEDs from the first duty cycle to the third duty cycle being inverse to a change in the duty cycle of the second group of LEDs from the second duty cycle to the fourth duty cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of operating a Light-Emitting Diode (LED) light having a light source that includes a first LED and a second LED coupled to a controller, the method comprising the steps of:
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supplying a current to the light source; supplying a first control signal to the controller; supplying a timing signal having a period; alternately pulsing the first LED and the second LED during the period, such that the first LED has a first duty cycle and the second LED has a second duty cycle during the period; supplying a second control signal to the controller, where the second control signal is different than said first control signal; and alternately pulsing the first LED and the second LED during the period, such that the first LED has a third duty cycle different than the first duty cycle and the second LED has a fourth duty cycle different than the second duty cycle during the period; wherein a change in the duty cycle of the first LED from the first duty cycle to the third duty cycle is inverse to a change in the duty cycle of the second LED from the second duty cycle to the fourth duty cycle. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A Light-Emitting Diode (LED) lighting system, comprising:
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a light source having first and second groups of light-emitting diodes (LEDs) and each group having at least one LED; a controller coupled to the light source for controlling the first and second groups of LEDs; a signal generator coupled to the controller for generating a timing signal for the controller, the timing signal having a period; the controller being operable to sense a current level supplied to the light source within a plurality of current ranges including a middle current range between a high current level and a low current level lesser than the high current level; and throughout the middle current range, the controller being operable to alternately pulse the first and second groups of LEDs during the period and to vary respective duty cycles of the first and second groups of LEDs inversely, and as a function of the current level supplied to the light source, between zero (0) percent and one-hundred (100) percent of the period. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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Specification