Inductive Clock Distribution in Superconducting D Flip-Flops

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Solution Overview

Problem

CMOS technology-based digital circuits face limitations in device size and power consumption, especially at high clock speeds, due to static power maintenance and current leakage even when inactive, leading to inefficiencies in high-performance systems like data center servers.

Innovation Solution

The development of a superconducting integrated circuit using a D flip-flop configuration with inductive coupling, Josephson junctions, and superconducting quantum interference devices, which stores and annihilates fluxons in response to clock pulses, eliminating the need for Josephson transmission lines and allowing for efficient clock distribution without static power dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If CMOS technology is used for digital circuits, then device integration is achieved, but power consumption increases due to static power maintenance and current leakage

Engineering Contradiction:
Improvedevice integrationVSAvoidpower consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent transitions from CMOS technology operating at room temperature to superconducting technology operating at cryogenic temperatures, fundamentally changing the operating parameters to eliminate resistive power loss and achieve zero static power consumption while maintaining high device integration

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the electronic field-based CMOS operation with quantum mechanical effects (Josephson effect, fluxon dynamics) in superconducting circuits, enabling logic operations without resistive dissipation and achieving ultra-low power consumption

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If CMOS circuits operate at high clock speeds, then processing performance improves, but power consumption increases due to dynamic and static power loss

Engineering Contradiction:
Improveprocessing performanceVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating temperature parameter to cryogenic levels where superconductivity occurs, enabling high-speed operation without the resistive losses that limit CMOS performance at high clock speeds, thereby achieving high productivity with minimal power consumption

Inventive Principle:
Principle #35Parameter changes

3Speed

If Josephson transmission lines are used for clock signal distribution, then clock signals can be transmitted, but device complexity and power consumption increase

Engineering Contradiction:
Improveclock signal transmissionVSAvoidcircuit complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent extracts the Josephson transmission line components from the clock distribution network and replaces them with passive superconducting inductive coupling elements, simplifying the circuit architecture while maintaining efficient clock signal transmission to multiple flip-flops

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the clock distribution function into individual inductive coupling paths from a central clock source to each flip-flop, eliminating the need for complex transmission line infrastructure and reducing overall device complexity

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables low-power operation with zero static power dissipation, reducing power consumption and increasing the number of logic circuits on a chip, while allowing for more efficient chip layout and alternative clock signal distribution methods.

Implementation Method 1

a first Josephson junction, JJ, coupled between the first terminal and a second terminal wherein the JJ is coupled between the first inductor and the second inductor

Methodology Applied
Scientific EffectJosephson effect: Josephson Effect

Implementation Method 2

a superconducting quantum interference device, SQUID, coupled between the third terminal and a fourth terminal wherein the SQUID is coupled between the second inductor and the third inductor

Methodology Applied
Scientific EffectSuperconducting quantum interference:

Implementation Method 3

an inductive loop, formed between the first JJ and the SQUID, is configured to in response to receiving a first clock pulse via the clock line, store a fluxon when a state of the input data signal is high

Methodology Applied
Scientific EffectMagnetic flux storage: Magnetic Field

Implementation Method 4

a clock line coupled to provide the clock signal to the at least one D flip-flop; and a return clock line, wherein the clock line and the return clock line are connected across a stacked driver to provide current for driving the clock signal

Methodology Applied
Scientific EffectInductive coupling: Electromagnetic Induction

Data Source

PatentEP3776856B1Superconducting integrated circuits with clock signals distributed via inductive coupling
Publication Date: 2024.05.01 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3776856B1 patent drawingFigure 1A~1B
  • EP3776856B1 patent drawingFigure 2
  • EP3776856B1 patent drawingFigure 3~4

AI summary

Superconducting integrated circuits with clock signals distributed via an inductive coupling and related methods are provided. A method includes providing a D flip-flop having a clock terminal coupled to receive clock pulses from a clock line, a data input terminal, and a data output terminal. The D flip-flop may further include a first Josephson junction (JJ) coupled between a first terminal and a second terminal. The D flip-flop may further include a superconducting quantum interference device (SQUID) coupled between a third terminal and a fourth terminal, where an inductive loop, formed between the first JJ and the SQUID, is configured to in response to receiving a first clock pulse, store a fluxon when a state of the input data signal is high, and is configured to in response to receiving a second clock pulse to annihilate the stored fluxon when a state of the input data signal is low.