A delta-sigma DC-to-DC converter comprises a pair of high-side and low-side switches switched to convert an input voltage to an output voltage, a sense circuit to sense the output voltage of the converter to generate a feedback signal, a transconductive amplifier to amplify a difference between the feedback signal and a threshold signal to generate a differential current, a charging circuit connected with the differential current to generate a charging voltage, and a driver to compare the charging voltage with two reference signals to generate the pair of low-side and high-side driving signals.