An apparatus of driving a light source for a display device is provided. The apparatus includes a temperature sensor (940) sensing a temperature and generating an output voltage based on the sensed temperature, a buffer (950) generating an output signal having a state depending on the output voltage of the temperature sensor (940), an oscillator (931) generating an oscillating signal having a frequency depending on the state of the output signal of the buffer, and an inverter (920) performing a switching operation in response to the oscillating signal from the oscillator (931). Therefore, the inverter (920) increases the voltage applied to the light source when the temperature near the light source is lower than a predetermined temperature since the frequency of the oscillating signal is increased.