A power converter circuit included in a computer system may charge and discharge a switch node coupled to a regulated power supply node via an inductor. During a charge cycle, the power converter circuit may generate a reference ramp signal that has an initial voltage level greater than that of the switch node. The power converter may also generate a sense ramp signal using the voltage level of the switch node, and halt the charge cycle using results of a comparison of the respective voltage levels of the reference ramp signal and the sense ramp signal.