There is provided a digital PWM generator according to a first exemplary embodiment of the present invention including: an A/D converter dividing a predetermined reference voltage into a plurality of sections corresponding to a predetermined first set value, searching a section to which the magnitude of an input voltage Vin corresponds, among the plurality of sections, and converting a value corresponding to the searched section into a digital signal; a frequency selector providing a counting number by counting a predetermined high-speed counting clock during a one-cycle section of a predetermined reference clock; and a PWM signal generator converting the digital signal from the A/D converter into a ratio value corresponding to a ratio for the reference voltage and generating a PWM signal having a controlled duty ratio of the reference clock by using the ratio value and the counting number from the frequency selector.