Abstract: One embodiment describes a Josephson current source system comprising a flux-shuttle loop that is inductively coupled with an AC input signal. The flux-shuttle loop includes a plurality of stages each comprising at least one Josephson junction. The plurality of stages can be spaced about the flux shuttle loop. Each of a plurality of pairs of the plurality of stages are configured to concurrently trigger in a sequence via the respective at least one Josephson junction in response to the AC input signal and to provide a respective pair of single-flux quantum (SFQ) pulses that move sequentially and continuously through each stage of the plurality of stages around the flux-shuttle loop via each of the at least one Josephson junction of each of the respective stages that results in a DC output current being provided through an output inductor.