Abstract: A controller is disclosed for controlling the optical output of at least one light emitting diode. The controller comprises a control unit and a power supply unit for supplying power to the at least one light emitting diode. The control unit is arranged to receive as input, first and second signals which are representative of the operating characteristics of the at least one light emitting diode, and which is further arranged to control the power output from the power supply unit to the at least one light emitting diode in dependence of the first and second signals. The first signal is representative of the current within the at least one light emitting diode and the second signal is representative of the temperature of the at least one light emitting diode so that the optical output from the at least one LED can be varied in accordance with the operating characteristics of the at least one light emitting diode.

Abstract: A controller is disclosed for controlling the optical output of at least one light emitting diode. The controller comprises a control unit and a power supply unit for supplying power to the at least one light emitting diode. The control unit is arranged to receive as input, first and second signals which are representative of the operating characteristics of the at least one light emitting diode, and which is further arranged to control the power output from the power supply unit to the at least one light emitting diode in dependence of the first and second signals. The first signal is representative of the current within the at least one light emitting diode and the second signal is representative of the temperature of the at least one light emitting diode so that the optical output from the at least one LED can be varied in accordance with the operating characteristics of the at least one light emitting diode.