A control circuit for a switching regulator having an inductor, comprising a first input for receiving a current measurement signal proportional to the magnitude and direction of current in the inductor, (or proportional to the difference in current in two inductors for an AC system having more than one phase); the current measurement signal being compared with a reference current representing the desired current in the inductor, the circuit having a processor to determine the timing of switching instances, and to control switching of said inductor between a positive voltage (charging configuration while the current is positive) and a negative voltage state (discharging configuration while the current is positive), where the processor determines the difference between said current measurement signal and said reference current signal to generate a current error signal representative of the difference or representative of the polarity of the difference, and the processor calculates timing of switching instances to achieve an average current error signal close to zero, based on timing of previous switching instances relative to zero crossing times of the current error signal during a previous excursion.