US 12,231,123 B2
Metastability-free clockless single flux quantum logic circuitry
Sergey Rylov, White Plains, NY (US); John Francis Bulzacchelli, Somers, NY (US); and Matthew Beck, Danbury, CT (US)
Assigned to International Business Machines Corporation, Armonk, NY (US)
Filed by International Business Machines Corporation, Armonk, NY (US)
Filed on Oct. 24, 2022, as Appl. No. 17/971,700.
Prior Publication US 2024/0137027 A1, Apr. 25, 2024
Prior Publication US 2024/0235558 A9, Jul. 11, 2024
Int. Cl. H03K 19/195 (2006.01); G06F 1/10 (2006.01); G06N 10/20 (2022.01); G06N 10/40 (2022.01); H03K 19/20 (2006.01)
CPC H03K 19/195 (2013.01) [G06F 1/10 (2013.01); G06N 10/20 (2022.01); G06N 10/40 (2022.01); H03K 19/1954 (2013.01); H03K 19/20 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A device, comprising:
a logic circuit comprising a clockless single flux quantum logic gate, wherein the clockless single flux quantum logic gate comprises:
a plurality of input ports, and an output port;
a plurality of dynamic storage loop circuits;
an output Josephson junction coupled to an output of each of the dynamic storage loop circuits and configured to drive the output port;
a plurality of isolation buffer circuits, wherein each isolation buffer circuit is coupled to a respective input port, and a respective dynamic storage loop circuit;
wherein each isolation buffer circuit comprises a Josephson junction that is configured to absorb a circulating current of an antifluxon without switching, which is injected into the respective dynamic storage loop circuit as a result of the output Josephson junction switching to generate a single flux quantum output pulse on the output port, to prevent the antifluxon from being output from the respective input port; and
wherein each isolation buffer circuit is configured to inject a fluxon into the respective dynamic storage loop circuit in response to a single flux quantum pulse applied to the respective input port, and annihilate an antifluxon that is present in the respective dynamic storage loop circuit.