Abstract: A first power supply voltage Vin1 of a first input section and a second power supply voltage Vin2 of the second input section satisfy an expression Vf(min)?Vin2<Vf(typ)<Vin1?Vf(max). A switching controller alternately electrically connects the first input section or the second input section to LEDs, and based on the difference between an average forward current detected by a detector and a target value of the average forward current, controls the ratio of a period of time for which the first input section is connected to the LEDs to a period of time for which the second input section is connected to the LEDs so that the value of the average forward current approaches the target value.