Patent ID: 8203288

Claim:
A light emitting diode array driving apparatus for driving a light emitting diode array having a plurality of light emitting diodes connected in series, in parallel, or in a mixed manner of serial and parallel connections, said apparatus comprising: a direct current-direct current converting part for converting an input voltage into a voltage appropriate for driving the light emitting diode array; a current/voltage detecting part for detecting a magnitude of a first current flowing through a switching element of the direct current-direct current converting part to correspondingly output a first current detection voltage, detecting a magnitude of a voltage across the light emitting diode array to correspondingly output a light emitting diode array detection voltage, and detecting a magnitude of a current flowing through the light emitting diode array to correspondingly output a second current detection voltage; and a constant current controlling part for controlling an on/off duty of the switching element according to the first current detection voltage, the second current detection voltage, and the light emitting diode array detection voltage detected by the current/voltage detecting part, wherein the constant current controlling part includes a pulse width modulation integrated circuit including an RT/T terminal for generating and outputting a sawtooth wave voltage of a predetermined frequency, a COMP terminal for receiving a comparison voltage to be compared with the sawtooth wave voltage, an output terminal for generating and outputting a pulse signal that is turned off during an interval where the sawtooth wave voltage is higher than the comparison voltage and turned on during an interval where the sawtooth wave voltage is lower than the comparison voltage, and a comparison voltage setter for setting the comparison voltage inputted to the COMP terminal, and when an overvoltage is applied to the light emitting diode array or the light emitting diode array is to be turned off by an external dimming control signal, the comparison voltage setter sets the comparison voltage to a value lower than a lower limit of the sawtooth wave voltage.