A method of driving a light source includes outputting a variable driving voltage to a light source part, sensing a first voltage based on the driving voltage and developed at a first end of the light source part, sensing a second voltage developed at a second end of the light source part due to current passing through the light source part and adjusting the driving voltage while using the first and second voltages so that power consumption by the light source part is substantially constant irrespective of temperature of the light source part and/or irrespective of a duty cycle ration being used to drive the light source part. Thus, a luminance of the light source part may be maintained at substantially uniform levels.