Patent ID: 8525432
Filing Date: 2013-09-03
Classification: H05B,Y02B

Abstract:
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 transistor and a resistor; a power supply connected to said LED; a digital potentiometer; said digital potentiometer supplying a variable output voltage to an operational amplifier; said operational amplifier having an output connected to said transistor to activate said transistor; said operational amplifier receiving a voltage developed across said resistor; wherein said activation of said transistor by said operational amplifier varies a current through said LED to control the brightness level of said LED; and said digital potentiometer is connected to a negative side of said resistor and to an output of a second operational amplifier to swamp an error of said digital potentiometer.