Conductive Thermal Management Architecture for Two-Card Assemblies

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Solution Overview

Problem

In two-card electronic assemblies, the heat-dissipating side of electronic modules is sandwiched between printed wiring boards, limiting air cooling and requiring effective thermal management to maintain junction temperatures below derated levels, especially in applications like deep space and underwater where heat dissipation is critical.

Innovation Solution

A conductive thermal management architecture using aluminum alloy stiffeners and wedge locks to secure electronic modules between PWBs, allowing for compressive force transfer and facilitating heat dissipation from both sides of the center stiffener to wedge lock mounting rails, enabling efficient heat flow and structural support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If electronic modules are placed directly on a PWB, then the structure is simple and easy to manufacture, but heat dissipation is limited because heat can only escape from one side

Engineering Contradiction:

Improvejunction temperatureVSAvoidthermal management structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The PWB is segmented into two separate card assemblies that can be independently manufactured and then assembled together. Each card has its own stiffener structure that provides thermal pathways, allowing heat to dissipate from both sides of the electronic modules rather than being constrained to a single PWB surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A center stiffener is introduced as an intermediary component between the two PWBs. This center stiffener provides a thermal pathway that conducts heat from the electronic modules to the outer surfaces of both PWBs, enabling bidirectional heat dissipation while maintaining structural integrity of the assembly.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If a rigid structure is used to secure electronic modules, then structural stability is improved, but ease of repair deteriorates because modules cannot be easily removed

Engineering Contradiction:

Improvestructural stabilityVSAvoidmodule replaceability

Core Design Contradiction:

Stability of the object's compositionVSEase of repair

Solution Approach 1:

The locking mechanism transitions from a static rigid fixation to a dynamic system that can be easily actuated. The locking tabs on the center stiffener can be manually actuated to release the clamps, allowing modules to be quickly removed and replaced while maintaining rigid structural stability during normal operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The locking function is extracted from the main structural components and integrated into the center stiffener as separate locking tabs. This allows the structural integrity to be maintained by the stiffener while the locking mechanism can be independently actuated to enable module removal without compromising the overall structural stability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If electronic modules are secured between two PWBs, then structural support is improved, but heat dissipation deteriorates because the heat-dissipating side is sandwiched between PWBs

Engineering Contradiction:

Improvestructural supportVSAvoidheat dissipation

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

Aluminum alloy stiffeners are introduced as composite structural elements between the two PWBs. These stiffeners provide both structural support to hold the electronic modules in place and thermal pathways to conduct heat away from the modules to the outer surfaces of the PWBs, simultaneously achieving both structural and thermal management objectives.

Inventive Principle:

Principle #40Composite materials

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 solution maintains MOSFET and diode junction temperatures below 125 degrees Celsius, meets vibration and pyroshock requirements, and allows for easy repair or replacement of electronic modules by making the center stiffener removable.

Implementation Method 1

wedge locks secure the center stiffener between the first stiffener and the second stiffener based on compressive force

Methodology Applied

Scientific EffectCompressive force transfer: Compression

Implementation Method 2

electronic components placed directly on a PWB dissipate heat through the PWB

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3876689B1Conductive thermal management architecture for electronic modules in a two-card assembly

Publication Date: 2023.08.23 HAMILTON SUNDSTRAND CORP

Figure 1A
Figure 1B
Figure 2

AI summary

A two-card assembly includes a first printed wiring board (PWB) (110a) on a first side of the two-card assembly, and a first stiffener (220) secured to the first PWB. The two-card assembly also includes a second PWB (110b) on a second side of the two-card assembly, and a second stiffener (130) secured to the second PWB A center stiffener (140) is disposed between the first stiffener and the second stiffener, and one or more electronic modules are secured to the center stiffener. The center stiffener dissipates heat from the one or more electronic modules.