Magnetoresistive Current Sensor Layout for Compact Accurate Detection

Solution Overview

Problem

Magnetic field detection apparatuses using magnetoresistive effect elements are large in size and lack high detection accuracy.

Innovation Solution

A current detection apparatus is designed with a bridge circuit comprising four magnetoresistive effect elements and a helical coil, where the coil's winding direction reverses at an intermediate point, and conductors generate induction magnetic fields orthogonal to the magnetoresistive effect films to enhance detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional magnetic field detection apparatuses using magnetoresistive effect elements are used, then detection function is provided, but the apparatus is large in size and lacks high detection accuracy

Engineering Contradiction:

Improvedetection accuracyVSAvoidapparatus size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The magnetoresistive effect film is divided into multiple regions (first end part, second end part, and intermediate part) with different magnetic field application strategies. Conductors are selectively positioned to apply magnetic fields only to the end parts, segmenting the magnetic field application to improve detection accuracy while reducing overall apparatus size.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The conductor is configured to extend in a direction inclined at 45 degrees relative to the magnetoresistive effect film's length direction, and magnetic fields are applied in a direction orthogonal to both the film length and conductor length. This three-dimensional spatial arrangement optimizes magnetic field coupling and detection accuracy while maintaining compact dimensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the conductor extends in the same direction as the magnetoresistive effect film, then结构简单 (structure is simple), but detection accuracy is insufficient

Engineering Contradiction:

Improvedetection accuracyVSAvoidconductor configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The conductor is configured to extend in a direction inclined at 45 degrees relative to the magnetoresistive effect film's length direction, and magnetic fields are applied in a direction orthogonal to both the film length and conductor length. This three-dimensional spatial arrangement optimizes magnetic field coupling and detection accuracy while maintaining compact dimensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If magnetic fields are applied to the entire magnetoresistive effect film, then detection coverage is complete, but the apparatus size increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidapparatus area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The magnetoresistive effect film is divided into multiple regions (first end part, second end part, and intermediate part) with different magnetic field application strategies. Conductors are selectively positioned to apply magnetic fields only to the end parts, segmenting the magnetic field application to improve detection accuracy while reducing overall apparatus size.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the magnetoresistive effect film are treated differently: the first end part and second end part receive magnetic field applications from conductors, while the intermediate part does not. This localized magnetic field application optimizes detection accuracy in critical regions while minimizing apparatus size and material usage.

Inventive Principle:

Principle #3Local quality

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 apparatus achieves high detection accuracy while maintaining a compact size by optimizing the magnetic field application to the magnetoresistive effect elements.

Implementation Method 1

a magnetoresistive effect element including a magnetoresistive effect film

Methodology Applied

Scientific EffectMagnetoresistive effect: Magnetoresistance

Implementation Method 2

The conductor is configured to be supplied with a current and thereby configured to generate an induction magnetic field to be applied to the magnetoresistive effect film

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250271471A1Magnetic field detection apparatus and current detection apparatus

Publication Date: 2025.08.28 TDK CORP

AI summary

A magnetic field detection apparatus includes a magnetoresistive effect element and a conductor. The magnetoresistive effect element includes a magnetoresistive effect film extending in a first axis direction and including a first end part, a second end part, and an intermediate part between the first and second end parts. The conductor includes a first part and a second part that each extend in a second axis direction inclined with respect to the first axis direction. The conductor is configured to be supplied with a current and thereby configured to generate an induction magnetic field to be applied to the magnetoresistive effect film in a third axis direction orthogonal to the second axis direction. The first part and the second part respectively overlap the first end part and the second end part in a fourth axis direction orthogonal to both of the second axis direction and the third axis direction.