Conductor Track Fuse Bottleneck Design for Thermal Protection

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Solution Overview

Problem

Electronic assemblies in control devices and braking systems face thermal overload and component damage due to defects, which existing conductor track fuses do not adequately address, especially under high-current conditions.

Innovation Solution

A conductor track fuse with a bottleneck of smaller cross-section, designed to overheat and break under excessive current, is integrated into the printed circuit board, featuring a copper constriction that lifts off and melts, effectively disconnecting the current flow and preventing further damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conductor track fuse with a bottleneck is used to protect against thermal overload, then the protection effectiveness is improved, but the risk of carbonization and parallel current paths increases

Engineering Contradiction:
Improveprotection effectivenessVSAvoidcarbonization and parallel current paths
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A solder layer is introduced as an intermediary substance between the conductor track and the substrate. This solder layer serves as a mediator that absorbs thermal energy and prevents direct carbonization of the substrate, thereby eliminating the harmful parallel current paths that could form through carbonized regions while maintaining the protective function of the bottleneck design

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the potentially harmful thermal energy that would cause carbonization into a beneficial effect by using the solder layer's melting and vaporization processes. The solder absorbs the thermal energy through phase changes, transforming the harmful heat into a protective mechanism that prevents substrate damage while maintaining circuit protection

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If the bottleneck cross section is reduced to ensure it is the weakest link, then the protection reliability is improved, but the susceptibility to carbonization increases

Engineering Contradiction:
Improveprotection reliabilityVSAvoidcarbonization susceptibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The solder layer acts as a protective intermediary between the reduced-cross-section bottleneck and the substrate. It prevents direct thermal contact that would cause carbonization, allowing the bottleneck to maintain its small cross section for reliable protection while the solder absorbs the thermal stress and prevents harmful side effects

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides a simple and cost-effective means to protect electronic assemblies from thermal overload by ensuring the conductor track fuse is the weakest link, melting to prevent excessive heat and damage to neighboring components, thereby ensuring safe operation.

Implementation Method 1

A faulty current in the component 2 leads to an increase in current in the conductor track 4, but especially at the narrow point 5 of the conductor track 4. This increases the temperature at this narrow point 5.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

Then the conductor track fuse 3 melts and thereby separates the current flow

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2168410B1Electronic module comprising a conductor fuse
Publication Date: 2018.05.16 CONTI TEMIC MICROELECTRONIC GMBH
  • EP2168410B1 patent drawingFigure 1~2
  • EP2168410B1 patent drawingFigure 3~4
  • EP2168410B1 patent drawingFigure 5~6

AI summary

The invention relates to an electronic module comprising a printed circuit board (1) provided with components (2), conductor tracks (4) and a conductor fuse (3) that protects against thermal overload. According to the invention, the conductor fuse (3) is embodied as a bottleneck (5) having a narrower cross section compared to the conductor tracks (4).