A method operates a DC-DC voltage converter. A current measurement circuit generates a current signal correlated with a coil current of a coil. A hysteretic switch control system electrically turns off a switch for driving the coil current, if the current signal signals a coil current greater than a peak comparison value, and electrically turns on the switch if the current signal signals a coil current lower than a valley comparison value. An actual value measurement circuit generates an actual value signal correlated with an electrical output variable of the DC-DC voltage converter. A controller unit adjusts the output variable to a prescribed setpoint value and, generates a comparison value signal depending on a control deviation and the switch control system sets an average value of the peak comparison value and generates the valley comparison value from the comparison value signal.