A backlight driver and a method of driving the same are disclosed. The backlight driver includes a vertical synchronization signal filter for generating a second vertical synchronization signal based on an input first vertical synchronization signal, and selecting one of the first vertical synchronization signal and the second vertical synchronization signal as a third vertical synchronization signal according to whether a period difference between adjacent first vertical synchronization signals satisfies a preset threshold range, a duty ratio detector for detecting a duty ratio of an input pulse width modulation (PWM) signal, a PWM generator for generating an output PWM signal synchronized with the third vertical synchronization signal output from the vertical synchronization signal filter and having the duty ratio and outputting the output PWM signal to a backlight unit.