Direct current powered clockless superconducting logic family using dynamic internal states

Patent metadata

Field	Value
Publication number	US-11115027-B2
Application number	US-202016850203-A
Country	US
Kind code	B2
Filing date	Apr 16, 2020
Priority date	Oct 30, 2018
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

Techniques regarding a DSFQ logic family are provided. For example, one or more embodiments described herein can comprise a system, which can comprise a dynamic single flux quantum logic circuit that has a self-resetting internal state and can be powered by direct current. Further, the self-resetting internal state can be characterized by two time constants.

First claim

What is claimed is:

1. An apparatus, comprising:
a first circuit branch comprising a first Josephson junction arranged in series with a resistor;
a second circuit branch connected in parallel with the first circuit branch and comprising a second Josephson junction, wherein the first circuit branch is a dynamic circuit branch and wherein the second circuit branch is a static circuit branch;
a superconducting inductor connected in series with a parallel connection of the first circuit branch and the second circuit branch; and
an output port electrically biased by an energy-efficient rapid single flux quantum bias source comprised of a limiter Josephson Junction connected in series with a second inductor.

2. The apparatus of claim 1 , wherein the superconducting inductor connected in series with the parallel connection of the first circuit branch and the second circuit branch establishes a dynamic self-resetting internal state characterized by a first time constant and a second time constant.

3. The apparatus of claim 2 , wherein the first time constant is an intrinsic constant to Josephson junctions.

4. The apparatus of claim 2 , wherein the second time constant is defined by the resistor.

5. A method, comprising:
forming a first circuit branch comprising a first Josephson junction arranged in series with a resistor; and
forming a second circuit branch coupled with the first circuit branch and comprising a second Josephson junction, wherein the first circuit branch is a dynamic circuit branch and wherein the second circuit branch is a static circuit branch.

6. The method of claim 5 , further comprising:
connecting a superconducting inductor in series with a parallel connection of the first circuit branch and the second circuit branch.

7. The method of claim 6 , wherein a first critical current of the first Josephson junction is a first value and a second critical current of the second Josephson junction is a second value, and wherein the first value is less than the second value.

8. The method of claim 5 , wherein the superconducting inductor connected in series with the parallel connection of the first circuit branch and the second circuit branch establishes a dynamic self-resetting internal state characterized by a first time constant and a second time constant.

9. The method of claim 8 , wherein the first time constant is an intrinsic time constant to Josephson junctions.

10. The method of claim 8 , wherein the second time constant is defined by the resistor.

11. An apparatus, comprising:
a first circuit branch comprising a first Josephson junction arranged in series with a resistor; and
a second circuit branch coupled with the first circuit branch and comprising a second Josephson junction, wherein the first circuit branch is a dynamic circuit branch and wherein the second circuit branch is a static circuit branch.

12. The apparatus of claim 11 , further comprising a superconducting inductor connected in series with a parallel connection of the first circuit branch and the second circuit branch.

13. The apparatus of claim 12 , wherein the superconducting inductor connected in series with the parallel connection of the first circuit branch and the second circuit branch establishes a dynamic self-resetting internal state.

14. The apparatus of claim 13 , wherein the dynamic self-resetting internal state is characterized by a first time constant and a second time constant.

15. The apparatus of claim 13 , wherein the first time constant is an intrinsic constant to Josephson junctions.

16. The apparatus of claim 13 , wherein the second time constant is defined by the resistor.

17. The apparatus of claim 11 , wherein a first critical current of the first Josephson junction is a first value and a second critical current of the second Josephson junction is a second value, and wherein the first value is less than the second value.

18. The apparatus of claim 11 , wherein a first critical current of the first Josephson junction is a first value and a second critical current of the second Josephson junction is a second value, and wherein the first value is equal to the second value.

19. The apparatus of claim 11 , wherein the resistor is an external shunt resistor adapted to damp the plasma resonance of the first Josephson junction and the second Josephson junction.

Assignees

• IBM

Inventors

• Rylov Sergey

Classifications

• H03K19/1952 Primary

  with electro-magnetic coupling of the control current · CPC title

• H03K3/38

  by the use, as active elements, of superconductive devices · CPC title

• G06F1/10

  Distribution of clock signals {, e.g. skew} · CPC title