Soft Magnet Sensor Device for Magnetic Field Concentration

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Solution Overview

Problem

Existing sensor devices face challenges in achieving accurate measurements while minimizing costs, particularly due to hysteresis effects and costly housings associated with core-based solutions.

Innovation Solution

A sensor device comprising a current conductor, a magnetic field sensor chip encapsulated with a soft magnet, where the magnetic field sensor chip and soft magnet are galvanically isolated by an encapsulation material, allowing the soft magnet to concentrate and homogenize the magnetic field for improved measurement accuracy and reducing the need for costly core-based designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If core-based measurement concepts are used, then measurement accuracy can be achieved, but hysteresis effects and cost-intensive housings occur

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidhysteresis effects

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the magnetic flux concentrating function from the traditional magnetic core and implements it through a soft magnet layer integrated directly with the sensor chip. This separation eliminates the need for a separate core structure, thereby avoiding hysteresis effects while maintaining measurement accuracy through direct magnetic field concentration at the sensor element location

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an encapsulation material as an intermediary between the sensor chip and the external environment. This encapsulation layer provides galvanic isolation and mechanical protection, replacing the need for cost-intensive housings while maintaining the functional integrity of the sensor device

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If core-based measurement concepts are used, then magnetic field concentration can be achieved, but cost-intensive housings are required

Engineering Contradiction:

Improvemagnetic field concentrationVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the magnetic flux concentrating function with the sensor chip structure itself by integrating a soft magnet layer directly onto the chip. This integration eliminates the need for separate core components and cost-intensive housings, reducing manufacturing complexity and cost while maintaining effective magnetic field concentration

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the material parameters of the sensor chip by incorporating soft magnetic materials with specific permeability characteristics. This parameter change enables the chip itself to concentrate magnetic flux effectively, replacing the need for traditional core structures and reducing manufacturing costs

Inventive Principle:

Principle #35Parameter changes

3Reliability

If galvanic isolation is implemented between sensor chip and soft magnet, then reliability is improved, but additional encapsulation material is required

Engineering Contradiction:

Improvegalvanic isolationVSAvoidencapsulation structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality in the encapsulation material, which simultaneously provides galvanic isolation between the sensor chip and soft magnet, mechanical protection, and structural support. This consolidation of multiple functions into a single component improves reliability without significantly increasing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances measurement accuracy by suppressing unwanted magnetic stray fields and allowing for absolute magnetic field detection, reducing geometric restrictions and operational costs by eliminating the need for differential magnetic field measurements and costly housings.

Implementation Method 1

a soft magnet secured to the encapsulation material and configured to concentrate the magnetic field at the location of the sensor element

Methodology Applied

Scientific EffectMagnetic field concentration: Magnetism

Implementation Method 2

The magnetic field sensor chip and the soft magnet are galvanically isolated from one another by the encapsulation material

Methodology Applied

Scientific EffectGalvanic isolation: Electrical Resistance

Data Source

PatentUS11726148B2Sensor devices having soft magnets and associated production methods

Publication Date: 2023.08.15 INFINEON TECHNOLOGIES AG

AI summary

A sensor device includes a current conductor designed to carry a measurement current, and a magnetic field sensor chip having a sensor element, wherein the magnetic field sensor chip is designed to detect a magnetic field at the location of the sensor element. The sensor device furthermore includes an encapsulation material, wherein the magnetic field sensor chip is encapsulated by the encapsulation material, and a soft magnet secured to the encapsulation material and designed to concentrate the magnetic field at the location of the sensor element. The magnetic field sensor chip and the soft magnet are galvanically isolated from one another by the encapsulation material.