Patent ID: 8264171
Filing Date: 2012-09-11
Classification: H05B

Abstract:
1. An LED (light emitting diode) circuit having temperature compensation, the circuit comprising: an LED terminal for connection to an LED device that is separate from the LED circuit; an LED driver configured to output an LED drive signal to operate the LED device to produce light; a first current source selectively connectable to the LED terminal and configured to output a first snoop current; a second current source selectively connectable to the LED terminal and configured to output a second snoop current; an amplification circuit configured to measure a forward voltage of the LED device when the LED device is driven by either the first snoop current or the second snoop current; and a temperature compensation circuit configured to receive a first measured forward voltage when the LED device is driven by the first snoop current and to receive a second measured forward voltage when the LED device is driven by the second snoop current, the temperature compensation circuit further configured to output an adjustment signal that is based at least on the first and second measured forward voltages, wherein the LED driver varies the LED drive signal depending on the adjustment signal.