A DC-DC digital pulse width modulated power supply is disclosed for generating a DC regulated output voltage. A digital control node has a digital control voltage disposed thereon for controlling the operation of the supply, wherein the digital control voltage has a substantially zero voltage when the output voltage of the supply is at a desired regulation, the digital control voltage having a resolution defined by a least significant bit (LSB). An input node receives a DC analog reference voltage defining the output voltage of the supply. A difference device determines the difference between the analog reference voltage and the output voltage to generate said digital control voltage. An LSB variation device varies the size of the LSB without varying the value of the digital control voltage for a substantially zero difference between the analog reference voltage and the output voltage.