In accordance with an embodiment, a method of operating a switched-mode power supply includes controlling a first switch coupled between an inductor and a reference node. Controlling includes modulating a first switching signal to control a first current through the first switch to a first predetermined current, and attenuating a current supplied by the first switch to the inductor in accordance with an attenuation factor to form an attenuated current. Attenuating includes providing a pulse modulated signal to a second switch coupled between the first switch and the inductor, where the attenuation factor is related to a pulse density of the pulse modulated signal.