The output voltage of a power converter is controlled by comparing the output voltage to a target output voltage during a first time interval and calculating an inductor current required in a second time interval immediately following the first time interval to increase the output voltage to the target output voltage. A duty cycle of a switch is varied to modify the current in the inductor during the second time interval according to the calculated inductor current. In one embodiment a fixed duty cycle response is provided if the output voltage is less than a predefined maximum and greater than a predefined minimum. In another embodiment the duty cycle of the switch is bounded by a predetermined maximum and minimum value.