The invention relates to a control method and a controller for a DC-DC converter, such as a synchronous Buck converter, which exploits the principle of capacitor charge balance to allow the converter to recover from a positive and/or negative load current step in the shortest achievable time, with the lowest possible voltage undershoot/overshoot. The control method may be implemented by either an analog or a digital circuit. The controller may be integrated with existing controller schemes (such as voltage-mode controllers) to provide superior dynamic performance during large-signal transient conditions while providing stable operation during steady state conditions. The invention also relates to a method and a modification of a DC-DC converter topology that comprises connecting a controlled current source between an input terminal and an output terminal of the DC-DC converter; detecting a load current step to a new load current; modifying a duty cycle of the DC-DC converter; and modifying current through a parallel output capacitor of the DC-DC converter by controlling current of the current source. The methods and circuits provided herein are applicable to Buck converters and Buck-derived converters such as forward, push-pull, half-bridge, and full-bridge converters.