Patent ID: 8378587

Claim:
A portable electric lamp, comprising: a light-emitting diode, an optic sensor situated near the light-emitting diode and designed to deliver a signal representative of light reflected by an object that is illuminated by the light-emitting diode and that is disposed at a variable distance from the lamp, and a control circuit connected to automatically regulate a power of the light-emitting diode as a function of the signal delivered by the optic sensor, the control circuit including: a servo-control circuit to adjust the power of the light-emitting diode via a power converter to servo-control the power of the light-emitting diode to a first manual setpoint, and to an automatic setpoint based on the optic sensor and a current intensity absorbed by the light-emitting diode; and a modulation input controlled by: a first error circuit receiving the first manual setpoint, a second error circuit in connection with the optic sensor, whose signal is compared with a second setpoint corresponding to a desired lighting level, and a third error circuit receiving an output signal of the second error circuit and a measurement signal of the current intensity flowing in a resistor in series with the light-emitting diode, an output of the third error circuit being connected to the first error circuit via an amplifier.