LED DRIVING DEVICE, LIGHT SOURCE DEVICE, AND LIQUID CRYSTAL DISPLAYING DEVICE

摘要

A first power supply voltage (Vin1) of a first input section, and a second power supply voltage (Vin2) of a second input section satisfy a relational expression: Vf (min) = Vin2 < Vf (typ) < Vin1 = Vf (max). Furthermore, a switching control unit makes the first input section and the second input section electrically-connected to LEDs, alternately, and also controls the ratio between the periods of time with which the first input section and the second input section are electrically-connected to the LEDs, based on the difference between an average forward current that was detected by a detecting unit, and the target value for the average forward current, so as to make the average forward current value draw nearer to the target value.