Patent ID: 8258707

Claim:
Lighting device, comprising: an LED; a driver for driving the LED; a controller for controlling the driver, the controller having a sensor input for receiving a measuring signal indicating a measured light level; wherein the LED is coupled to the sensor input of the controller; wherein the controller is capable of operating in a drive state and in a measuring state and is configured, during operation, to alternate between the drive state and the measuring state; wherein, in the drive state, the controller is configured to generate a control signal for the driver such that the LED generates light; and wherein, in the measuring state, the controller is configured to generate the control signal for the driver such that the driver does not generate any LED current, and to process an input signal received from the LED as a light measuring signal; so that the LED is alternatively used for generating light and sensing light, wherein, in the measuring state, the controller is configured to make a determination on the desired light output of a LED on the basis of the input signal received from the LED; and wherein, in the drive state, the controller is configured to generate the control signal for the driver such that an average light output produced by the LED corresponds to the desired light output, as determined in the measuring state.