Patent ID: 7129870

Claim:
A circuit comprising: a latch circuit including a Josephson junction and configured to perform a latch operation based on a hysteresis characteristic in response to a single flux quantum; a load circuit including load inductance and load resistance and coupled to an output of said latch circuit; and a reset circuit provided between the output of said latch circuit and said load circuit and configured to reset said latch circuit a predetermined time after the latch operation by said latch circuit, wherein said Josephson junction is driven by a direct current and the reset circuit includes a resistance R and an inductance L such that the predetermined time is responsive to a time constant determined by the resistance R and the inductance L, and wherein said resistance R and said inductance L are connected in series to provide a coupling between the output of said latch circuit and a ground potential, inductance Lload of said load inductance, resistance Rload of said load resistance, a gap voltage Vg of said Josephson junction, and a critical current Ic of said Josephson junction are related as: R<Vg/Ic, R<<Rload, L>>Lload, and L/R>>L load/ R load.