Cryogenic Link Cooling Assembly for Thermal Management
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Solution Overview
Problem
Cryogenic digital systems face challenges in efficiently transferring voltage and current between different temperature domains, leading to heat flow issues due to thermal conduction and electrical heating, which affects energy efficiency and signal integrity.
Innovation Solution
The implementation of multi-conductor signal links with cooling assemblies, such as cold plates and orthogonal cold strips, to thermally clamp the links at the appropriate temperature domain, minimizing thermal power flow and impedance discontinuity, thereby reducing signal interference and enhancing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper conductors are used to transfer voltage and current between temperature domains, then electrical conduction is achieved, but thermal conduction and electrical heating cause heat flow into the low temperature domain
Solution Approach 1:
The conductor path is segmented into superconducting segments (at low temperature) and normal conducting segments (at high temperature). The superconducting segments carry current without resistance and minimal thermal conduction, while the normal conducting segments are minimized in length. This segmentation allows the system to achieve reliable signal transfer while reducing the overall heat flow into the cryogenic domain by utilizing the superconducting state for the majority of the current path.
Solution Approach 2:
The system changes the physical state parameter of the conductor material by cooling it below its critical temperature to transition from normal conducting state to superconducting state. This parameter change (temperature) fundamentally alters the electrical and thermal properties, enabling near-zero electrical resistance and reduced thermal conduction, thereby solving the heat flow problem while maintaining reliable signal transfer.
2Loss of energy
If cooling assemblies are added to thermally clamp links, then thermal power flow is reduced, but device complexity increases
Solution Approach 1:
The cooling assembly is merged with the existing conductor structure by integrating cold plates or cold strips directly onto the conductor support structures or substrates. This integration allows the cooling function to be achieved without adding separate, complex cooling systems. The cold plates are thermally coupled to the low-temperature domain and directly clamp the conductor links, reducing thermal power flow while minimizing additional device complexity through functional integration.
3Use of energy by moving object
If superconducting segments are maximized, then energy efficiency is improved, but impedance discontinuity may occur at temperature domain boundaries
Solution Approach 1:
The system applies local quality by creating distinct regions with different thermal and electrical properties. The superconducting segments have zero electrical resistance and specific impedance characteristics, while the normal conducting segments have finite resistance and different impedance. By carefully designing the transition regions and matching impedances locally at the boundaries between superconducting and normal conducting segments, the system maximizes energy efficiency in the superconducting regions while maintaining signal integrity through localized impedance management.
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 effectively reduces thermal power flow and signal interference, achieving improved energy efficiency and signal integrity by maximizing the superconducting segment of the links and minimizing attenuation, with potential energy efficiency of 0.1 pico-Joules per bit and cost per bit less than 1.4 times standard 8/16 Gb core.
Implementation Method 1
Heat flow to the second temperature domain in a cryogenic digital system is a concern... thermal conduction... electrical heating
Implementation Method 2
a signal on a segment of the link in the one temperature domain may be superconducting
Implementation Method 3
Copper conductors are used to transfer the voltage and current between components in the temperature domains. The voltage and current on the copper conductors contribute heat into the low temperature domain using two mechanisms: a first mechanism is thermal conduction
Implementation Method 4
The voltage and current on the copper conductors contribute heat into the low temperature domain using two mechanisms: a first mechanism is thermal conduction and the other mechanism is electrical heating
Data Source
AI summary
The embodiments herein describe technologies of cryogenic digital systems with a first component located in a first cryogenic temperature domain and a second component located in a second cryogenic temperature domain that is lower in temperature than the first cryogenic temperature domain. An electrical conductor is coupled between the first component and the second component along a first plane. The electrical conductor carries a signal between the first component and the second component. A cooling assembly is coupled to a segment of the electrical conductor. The cooling assembly may include an electrical insulator including ceramic material. The cooling assembly may include a cold plate, two cold plates, or an orthogonal cold strip.