Metal Clip Current Shunt Layout for Stable High-Current Sensing

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Solution Overview

Problem

Existing techniques for current measurement in power semiconductor applications, particularly at high currents like 10 A or more, are inaccurate due to temperature-related issues and material limitations.

Innovation Solution

A metal clip with a multi-bridge configuration using resistive alloys for high electrical resistance and thermally conductive metals, where the temperature coefficient of the bridge spans is lower than the landing pads, allowing for accurate current measurement without excessive heat generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing current measurement techniques are used in power semiconductor applications, then current measurement can be obtained, but measurement precision deteriorates at high currents due to temperature-related issues and material limitations

Engineering Contradiction:

Improvecurrent measurement precisionVSAvoidmeasurement reliability at high currents

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The measurement path is segmented into multiple bridge spans (first bridge span, second bridge span, etc.) connected in series between landing pads. Each bridge span is made of material with low temperature coefficient, and the segmented structure allows better thermal management and maintains measurement precision at high currents where existing techniques fail

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure combining landing pads (made of material with higher temperature coefficient) and bridge spans (made of material with lower temperature coefficient). This composite approach allows the landing pads to provide good electrical contact while the bridge spans maintain stable resistance characteristics for accurate measurement at high currents

Inventive Principle:

Principle #40Composite materials

2Measurement precision

If high electrical resistance is used for accurate current measurement, then measurement precision improves, but temperature increases due to excessive heat generation

Engineering Contradiction:

Improvecurrent measurement precisionVSAvoidtemperature of measurement component

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

Different parts of the measurement component have different material properties: landing pads use material with higher temperature coefficient for good electrical contact, while bridge spans use material with lower temperature coefficient for stable resistance. This local differentiation allows accurate measurement without excessive heat generation in critical measurement regions

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the temperature coefficient parameter by selecting materials with different thermal characteristics for different parts of the measurement component. The bridge spans use material with lower temperature coefficient to maintain stable resistance at elevated temperatures, thereby preventing the temperature-masurement precision degradation loop

Inventive Principle:

Principle #35Parameter changes

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

The solution provides precise current measurement at high currents by maintaining stable electrical resistance and low temperature, preventing overheating and ensuring accurate voltage drops across the metal clip.

Implementation Method 1

the metal clip is arranged to conduct a shunt current from the first landing pad to the third landing pad, wherein the first and second bridge spans comprise sections of a first conductive material that the shunt current must pass through

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the first, second third landing pads are respectively thermally conductively attached to first, second and third contact pads from the structured metallization layer

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11810888B2Current shunt with reduced temperature relative to voltage drop

Publication Date: 2023.11.07 INFINEON TECHNOLOGIES AG

AI summary

An electronic device includes a structured metallization layer including a plurality of contact pads that are electrically isolated from one another, and a metal clip connected in a current shunt measurement arrangement with a semiconductor device, wherein the metal clip includes first, second and third landing pads, a first bridge span connected between the first and second landing pads, and second bridge span connected between the second and third landing pads, wherein the first, second third landing pads are respectively thermally conductively attached to first, second and third contact pads from the structured metallization layer, and wherein the second mounting pad is electrically floating.