Controlling a light source driving circuit and a power controller

Providing the driver circuit and controlling the light source power controller. Driving circuit comprising: a light source in series with the first inductor and the power source; a controller for controlling the switching of the first inductive coupler; current monitor configured to provide an indication of both flowing through the first switch is turned on and off when the a first inductor current signal; a second inductor, for monitoring the condition of the first inductor, the first inductor and the second inductor are connected to the common node, the common node located between the first inductor and the switch and the controller reference, the driving circuit with reference to different; a filter for providing a second signal indicative of the average current through the first inductor according to the first signal; and an error amplifier according to a second indication signal and reference signal generating target current value of the error signal, the error signal wherein the controller controls the switch so that the average current flowing through the light source is equal to the target current value. Output current drive circuit can be more precisely controlled.