Patent ID: 7804258
Filing Date: 2010-09-28
Classification: H05B,Y02B

Abstract:
1. A circuit, comprising: a light emitting diode (LED) circuit comprising a plurality of LEDs; a DC-DC boost circuit coupled to the LED circuit, the DC-DC boost circuit providing a first voltage and receiving a second voltage, wherein the plurality of LEDs are connected in-series between a first node for providing the first voltage and a second node, and wherein the plurality of LEDs are configured to conduct an LED circuit current; a first transistor having a first characteristic that varies over at least one of temperature and process, wherein the first transistor having a first current electrode coupled to the DC-DC boost circuit, the first transistor also having a second current electrode coupled to a ground terminal, and having a control electrode, wherein the first current electrode of the first transistor is coupled to the second node for receiving the LED circuit current, and wherein a feedback voltage, generated at the second node as a result of the LED circuit current and a first resistance of the first transistor between the second node and the ground terminal, is supplied as the second voltage to the DC-DC boost circuit; a control circuit, comprising: