Patent ID: 8786129

Claim:
A control device that controls lighting of a plurality of LEDs and detects a breakage of each LED, the control device comprising: a plurality of LED arrays connected in parallel to one another, each of the plurality of LED arrays including one or more LEDs connected in series and a resistance element connected in series to the LEDs; a voltage application circuit that applies a voltage to the plurality of LED arrays; a switching element disposed between the plurality of LED arrays and a ground; a voltage detection circuit having an end connected between the switching element and the plurality of LED arrays; a capacitor having an end connected between the switching element and the plurality of LED arrays, and another end connected to the ground; and a control circuit that controls the voltage outputted from the voltage application circuit and switching of conduction states of the switching element, and reads a voltage from the voltage detection circuit, wherein the resistance elements connected in series to the corresponding LEDs have different resistances from one another, the control circuit renders the switching element be in a connection state, and outputs a command signal to the voltage application circuit to apply the voltage for lighting the LEDs, and the control circuit renders the switching element in a disconnection state, and outputs a command signal to the voltage application circuit to apply a rectangular wave pulse voltage having a pulse duration that does not cause the LEDs to be lighted, to detect presence or absence of breakages of the LEDs in each LED array based on the voltage read from the voltage detection circuit and determine which of the LED arrays is broken.