Patent ID: 8278837
Filing Date: 2012-10-02
Classification: H05B,Y10T

Abstract:
1. A circuit for driving multiple sets of light emitting diodes (LEDs), the circuit comprising: a first set of LEDs comprised of one or more LEDs in series; a second set of LEDs comprised of one or more LEDs in series, wherein the first set of LEDs is configured to produce different color or color spectrum than the second set of LEDs; a third set of LEDs comprised of one or more LEDs in series, wherein the third set of LEDs is configured to produce, different color or color spectrum than the first and second sets of LEDs; a single inductor connected in series with the first, second, and third sets of LEDs; a first shunting transistor connected in parallel with the second set of LEDs; a single controller connected to the single inductor and the first shunting transistor, wherein the controller is configured to control a first duty cycle of the first shunting transistor: a second shunting transistor connected in parallel with the third set of LEDs, wherein the controller is connected to the second shunting transistor and the controller is configured to control a second duty cycle of the second shunting transistor; Wherein the one or more LEDs of the first set of LEDs are configured to produce red color, the one or more LEDs of the second set of LEDs are configured to produce blue color, and the one or more LEDs of the third set of LEDs are configured to produce-green color; and wherein the first set of LEDs is not connected in parallel with a shunting transistor.