The disclosure describes a DC-DC switching converter providing a peak-current servo, employing a pulse-frequency modulation (PFM) control signal and a constant on-time. A Buck, Boost, Buck-Boost, or similar switching converter that supports PFM mode is required, using a fixed on-time scheme for PFM. A final value of the coil current is sampled, and the sampled value of the coil current is compared to a target value for the coil current, to establish whether it is greater or less than the target value. The on-time of the high side device is adjusted to bring the final value of the coil current closer to the target value, using an adaptive coil current measurement.