Patent ID: 7847783

Claim:
A controller for a light-emitting diode (LED) array, comprising: DC/DC converter circuitry configured to supply power to an LED array, said LED array comprising at least a first string of LEDs and a second string of LEDs coupled in parallel together, each said string comprising at least two LEDs; and feedback circuitry comprising an amplifier circuit and a switch, said amplifier circuit configured to receive a first feedback signal from said first string of LEDs and a second feedback signal from said second string of LEDs, said first feedback signal is proportional to a current in said first string of LEDs and said second feedback signal is proportional to a current in said second string of LEDs, said amplifier circuit is further configured to compare said first and second feedback signals and to output a compared value based on, at least in part, said comparing said first and said second feedback signals, said amplifier circuit is further configured to control said switch to adjust a voltage drop across said switch to adjust the current in said first string of LEDs relative to the current in said second string of LEDs, based on said compared value.