Abstract: When a current which is conducted from a direct current power supply 8 to a choke coil L1 after a switching transistor 7 is turned on has a predetermined value, an LED lighting device. lights up an LED series circuit by conducting a pulse-shaped current which occurs by turning off the switching transistor 7 to the LED series circuit. A cycle period at which the pulse-shaped current is generated is determined according to the average value of the current flowing through the LED series circuit by using an oscillator (VCO) 4. The LED lighting device controls each of the pulse-shaped current value and the average current value arbitrarily.

Abstract: A headlamp LED lighting apparatus, which lights an LED block 2 having a plurality of LEDs connected in series, samples the output voltage of the headlamp LED lighting apparatus, calculates the average voltage during every prescribed interval, and has a storage unit for storing the average voltage during every prescribed interval calculated. A control circuit 8 compares the voltage variation in the average voltage during every prescribed interval read out of the storage unit with a prescribed threshold, and decides an LED failure of the LED block 2 from a result of the comparison.

Abstract: When a current which is conducted from a direct current power supply 8 to a choke coil L1 after a switching transistor 7 is turned on has a predetermined value, an LED lighting device lights up an LED series circuit by conducting a pulse-shaped current which occurs by turning off the switching transistor 7 to the LED series circuit. A cycle period at which the pulse-shaped current is generated is determined according to the average value of the current flowing through the LED series circuit by using an oscillator (VCO) 4. The LED lighting device controls each of the pulse-shaped current value and the average current value arbitrarily.