Patent ID: 8044609
Filing Date: 2011-10-25
Classification: H05B

Abstract:
1. A circuit for controlling a plurality of light emitting diode (LED) light sources, said circuit comprising: a converter operable for converting an input voltage to an output current and for providing said output current to said LED light sources; a feedback circuit coupled to said LED light sources and operable for generating a plurality of feedback signals indicative of a plurality of LED currents flowing through said LED light sources respectively; a current distribution controller coupled to said feedback circuit and operable for generating a plurality of control signals based on said feedback signals respectively so as to regulate said LED currents flowing through said LED light sources respectively, and also operable for controlling said converter to regulate said output current based on said feedback signals; a plurality of diodes, each of said diodes coupled between said converter and a corresponding LED light source of said LED light sources; a transformer operable for receiving a rectified AC voltage and for providing said output current to said LED light sources; a power switch coupled to said transformer and operable for regulating said output current; and an error amplifier operable for generating a first error signal to control said power switch, wherein a positive input of said error amplifier receives a first reference signal which is proportional to both a first voltage signal and a second voltage signal, wherein a negative input of said error amplifier receives a third voltage signal, wherein said first voltage signal is proportional to said rectified AC voltage, wherein said second voltage signal indicates said output current from said converter, and wherein said third voltage signal is proportional to a current flowing through a sense resistor coupled to said power switch.