Method and circuit for driving a low voltage light emitting diode

摘要

In a method for producing a control signal for regulating a drive current for driving an LED, a current through the LED is sensed, wherein the LED is driven by a power converter output, and wherein an output voltage of the power converter is proportionately controlled by a control signal. Next, a power supply voltage is sensed. The control signal is produced for the power converter, wherein the control signal is proportional to a difference between a reference voltage and the current through the LED. The control signal is then offset in response to the power supply voltage to reduce the current through the LED as the power supply voltage drops.