A digital control apparatus for a switching DC-DC converter includes at least one power transistor and is able to provide a regulated output voltage on a load. The apparatus includes digital control having a reference digital input signal and provides a modulating signal to a PWM device to which is input the modulating signal and which provides an output square wave signal for driving the power transistor of the DC-DC converter such that there is non-linear modulation only when the value of a signal on the load is lower or higher than a prefixed value range.