The present invention relates to a backlight unit for minimizing a change of a diving current. The backlight unit includes a light source; a constant current switching element which is connected between the light source and a detection node and controls a diving current supplied to the light source; a detection resistor connected between the detection node and a ground; a constant current control part which controls the operation of the constant current switching element based on the driving current control signal from the outside and the detection voltage from the detection node; and a driving current correcting part which generates a driving current control signal and corrects the size of the driving current control signal based on the detection voltage. So, a resistance value can be automatically corrected according to the detection result.
