CONTROL OF LIGHT INTENSITY USING PULSES OF A FIXED DURATION AND FREQUENCY
First Claim
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1. A device comprising:
- a first power potential;
a second power potential;
light source; and
a current switch connected to the light source including an input to receive a current switch control signal to place the switch in one of an ON state and an OFF state including a timing cycle with a series of pulses of fixed duration and fixed frequency within the timing cycle to cause current to flow from the first potential to the second potential through the light source during the ON state to cause the light source to emit light of a desired intensity over the timing cycle.
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Abstract
A method and circuit to control the intensity of lights, illumination fixtures, and displays using pulses of a fixed duration and a fixed frequency (FD/FF) is provided. In particular, the method may be used to control one more light sources. By varying the number of pulses in a control burst, the total current flowing through the light source may be precisely controlled providing greater accuracy than other methods, such as, for example, PWM or variable pulse frequency. The FD/FF technique may be used in conjunction with any number of light sources, and finds particular application in LED displays and for any type of LED illumination fixture.
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Citations
19 Claims
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1. A device comprising:
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a first power potential; a second power potential; light source; and a current switch connected to the light source including an input to receive a current switch control signal to place the switch in one of an ON state and an OFF state including a timing cycle with a series of pulses of fixed duration and fixed frequency within the timing cycle to cause current to flow from the first potential to the second potential through the light source during the ON state to cause the light source to emit light of a desired intensity over the timing cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A light source intensity control method to control the intensity of a light source, the method comprising:
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providing a timing cycle; determining a desired intensity the light source; generating a control signal including a series of pulses of fixed duration and fixed frequency within the timing cycle corresponding to the desired intensity; and supplying control signal to an input of a current switch connected to the light source to place the switch in one of an ON state during each pulse and an OFF state after each pulse to cause current to flow from a first potential to a second potential through the light source during the ON state and cause the light source to emit light of the desired intensity over the timing cycle. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification