System and Method For Controlling an Output Illumination Level of a Lighting System
First Claim
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1. A system for controlling a brightness level of a Light Emitting Diode comprising:
- a Light Emitting Diode (LED);
said LED connected in series with a field effect transistor and a resistor;
a digital potentiometer;
said digital potentiometer supplying a variable output voltage to an operational amplifier;
said operational amplifier connected to said field effect transistor to activate said field effect transistor;
a power supply connected to said LED;
wherein said activation of said field effect transistor by said operational amplifier varies a voltage across said resistor adjusting the brightness level of said LED.
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Abstract
A method of controlling a brightness level of an LED by supplying power to an LED in series with a field effect transistor and a resistor. A first voltage is supplied from a digital potentiometer to an operational amplifier. The field effect transistor is activated based on the first voltage from the operational amplifier and a second voltage is varied across the resistor when the field effect transistor is activated. The varying of the second voltage across the resistor causes a change in the brightness level of the LED.
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Citations
38 Claims
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1. A system for controlling a brightness level of a Light Emitting Diode comprising:
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a Light Emitting Diode (LED); said LED connected in series with a field effect transistor and a resistor; a digital potentiometer; said digital potentiometer supplying a variable output voltage to an operational amplifier; said operational amplifier connected to said field effect transistor to activate said field effect transistor; a power supply connected to said LED; wherein said activation of said field effect transistor by said operational amplifier varies a voltage across said resistor adjusting the brightness level of said LED. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of controlling a brightness level of an LED comprising the steps of:
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supplying power to an LED; the LED being in series with a field effect transistor and a resistor; supplying a first voltage from a digital potentiometer to an operational amplifier; activating the field effect transistor based on the first voltage from the operational amplifier; varying a second voltage across the resistor when the field effect transistor is activated; wherein the varying of the second voltage across the resistor changes the brightness level of the LED. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of controlling a brightness level of an LED comprising the steps of:
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supplying power to an LED; the LED being in series with a field effect transistor and a resistor; supplying a first voltage from a digital potentiometer to a first operational amplifier; activating the field effect transistor based on the first voltage from the first operational amplifier; wherein the varying of the second voltage across the resistor changes the brightness level of the LED. varying a second voltage across the resistor when the field effect transistor is activated; outputting a third voltage from a second operational amplifier and a voltage from a negative side of the resistor to an input of the digital potentiometer to swamp the error of the digital potentiometer. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A system for controlling an output illumination level of a lighting system comprising:
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a power source; an illumination device coupled to said power source; a voltage converter coupled to said illumination device; a load coupled to said voltage converter; a controller coupled to said power source and said switching device; said controller providing a variable voltage to said load such that a total current passing through said illumination device varies; and wherein the output illumination level of said illumination device varies according to the variable current passing through said illumination device. - View Dependent Claims (33, 34, 35, 36, 37, 38)
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Specification