US 4,538,077 A · Circuit utilizing Josephson effect

Abstract

A circuit utilizing Josephson junctions to perform high speed logic gate switching functions. Three "Y" connected resistors have Josephson junction devices at their non-connected ends. The resistances of the resistors, the critical currents of the Josephson junctions, and the amplitudes of input currents to two of the resistor-Josephson junction connections are selected so that, when the input currents are applied at the same time, the third Josephson junction is switched to the voltage state and both input currents are derived from the third Josephson junction-resistor connection as an input current. In another embodiment, the basic circuit has additional resistor-Josephson junction input arms, producing an M/N logic gate function. In another embodiment, the resistors are ".DELTA." connected. The resulting logic gates have wide operational margins, high speed switching capabilities and small size.

Claims16

Dependent claims

A circuit utilizing a plurality of Josephson junctions each of which switches from a zero voltage state to a voltage state in response to a current greater than its respective critical current, said circuit comprising:

a first resistor, a second resistor and a third resistor having predetermined resistances R.sub.1, R.sub.2, R.sub.3, respectively, each of said resistors having first and second ends and all of said resistors being connected together at said second ends thereof, said first ends of said first and second resistors receiving input currents and said first end of said third resistor providing an output current;
a first Josephson junction and a second Josephson junction having predetermined critical currents I.sub.01 and I.sub.02, respectively, and connected between a reference potential and the first end of said first and second resistors, respectively;
and
a specific Josephson junction having a predetermined critical current I.sub.03 and connected in series with said third resistor.

1 more element

A circuit utilizing a plurality of Josephson junctions, each of which switches from a zero voltage state to a voltage state in response to a current greater than its respective critical current, said circuit comprising:

a first resistor and a second resistor having predetermined resistances R.sub.1 and R.sub.2, respectively, each of said resistors having first and second ends, said resistors being connected at said second ends;
a first Josephson junction and a second Josephson junction connected between said first ends of the first and second resistors, respectively and a reference potential, and having predetermined critical currents I.sub.01 and I.sub.02, respectively;
a specific Josephson junction having a predetermined critical current I.sub.0 and connected between said interconnected second ends of said first and second resistors and said reference potential;
and a third resistor connected between said first ends of said first and second resistors and having a predetermined resistance R.sub.5.

1 more element

Dependencies are inferred from the claim text.

Circuit utilizing Josephson effect

Life of this patent

Circuit utilizing Josephson effect

Life of this patent

Abstract

Claims16