Patent ID: 8421375
Filing Date: 2013-04-16
Classification: F21V,H05B,Y02B

Abstract:
1. A light emitting apparatus comprising: a voltage source for supplying an input voltage; a light emitting diode electrically coupled to the voltage source; a pulse width modulation controller for controlling a duty cycle of the input voltage supplied; a first resistor electrically coupled between the voltage source and the light emitting diode; and an amplification circuit electrically coupled to the first resistor and the pulse width modulation controller for supplying a feedback voltage to the pulse width modulation controller the feedback voltage being proportionally changed relative to a resistor voltage measured across the first resistor, a current through the first resistor or a resistance of the first resistor, wherein the amplification circuit includes a first transistor and a second transistor, and wherein the amplification circuit includes a second resistor coupled in parallel with the first resistor for dividing an input current between the first and second transistors.