Patent ID: 8183788

Claim:
A LED luminance control circuit comprising one or several LEDs and a driving circuit, the driving circuit being connected in series with said one or several LEDs to provide energy to the one or several LEDs, wherein a control circuit is connected in parallel on both terminals of said one or several LEDs, and controls on/off of the LED connected in parallel thereto; and wherein said control circuit comprises: an input terminal, an operation amplifier, a N-type MosFET switch element, four resistors R 1 , R 2 , R 3 , R 4 , and a capacitor C, wherein the output terminal of the operation amplifier is connected to the gate of the switch element; one terminal of each of the resistors R 1 and R 2 is connected to the positive input terminal of the operation amplifier, the other terminal of the resistor R 1 is connected to one terminal of the capacitor C and the source of the switch element, the other terminal of the resistor R 2 is the input terminal, and the other terminal of the capacitor C is grounded; one terminal of each of the resistors R 3 and R 4 is connected to the negative input terminal of the operation amplifier, the other terminal of the resistor R 3 is grounded, and the other terminal of the resistor R 4 is connected to the output terminal of the operation amplifier; the drain and source of the switch element are connected to the positive terminal and negative terminal of the one or several LEDs to be controlled, respectively.