3D Magnetic Field Sensor with Orthogonal Sensing Elements

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Solution Overview

Problem

Conventional magnetic switches can only sense magnetic fields above a threshold in one or two dimensions, limiting their ability to detect fields in any direction.

Innovation Solution

A magnetic field sensor comprising three magnetic field sensing elements with different maximum response axes, coupled with an electronic circuit that includes threshold generators and comparators to detect magnetic fields in three dimensions by generating and comparing signals along orthogonal axes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional magnetic switches are used, then the device structure is simple, but the sensing capability is limited to one or two dimensions

Engineering Contradiction:
Improvesensing capabilityVSAvoiddevice structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The magnetic field sensor is divided into three separate magnetic field sensing elements, each responsible for sensing the magnetic field in a specific dimension (x, y, or z axis). This segmentation allows the system to achieve three-dimensional sensing capability while keeping each individual sensing element relatively simple in structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from two-dimensional sensing to three-dimensional sensing by adding a third sensing element oriented along the z-axis. This dimensional expansion enables the sensor to detect magnetic fields in any direction by combining the outputs from all three orthogonal sensing elements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple magnetic field sensing elements are used to achieve three-dimensional sensing, then the sensing coverage is improved, but the circuit complexity increases

Engineering Contradiction:
Improvesensing coverageVSAvoidcircuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the processing functions for all three magnetic field sensing elements into a single integrated circuit. The electronic circuit includes threshold generators and comparators that process signals from all three sensing elements (first, second, and third) in an unified manner, reducing overall system complexity despite the increased sensing capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electronic circuit is designed with universal functionality to handle signals from multiple sensing elements. The comparators and threshold generators can process signals from any of the three sensing elements, making the circuit multi-functional and adaptable to different sensing configurations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If three magnetic field sensing elements with orthogonal orientations are implemented, then three-dimensional detection capability is achieved, but the number of components increases

Engineering Contradiction:
Improvedetection capabilityVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The sensor system is segmented into three distinct sensing elements, each with a specific orientation (x-axis, y-axis, or z-axis). This segmentation is necessary to achieve three-dimensional detection capability, as each element contributes unique directional information that cannot be obtained from the other elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system achieves three-dimensional detection by adding sensing elements in additional spatial dimensions. The first sensing element detects fields along the x-axis, the second along the y-axis, and the third along the z-axis, collectively providing omnidirectional sensing capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Enables the detection of magnetic fields above thresholds in any dimension, providing a three-dimensional magnetic switch capability with efficient power management and sensitivity adjustment.

Implementation Method 1

Hall Effect elements generate an output voltage proportional to a magnetic field

Methodology Applied
Scientific EffectHall Effect: Hall Effect

Implementation Method 2

magnetoresistance elements change resistance in proportion to a magnetic field

Methodology Applied
Scientific EffectMagnetoresistance: Magnetoresistance

Data Source

PatentEP2997390B1Magnetic field sensor for detecting a magnetic field in any direction above thresholds
Publication Date: 2017.09.06 ALLEGRO MICROSYSTEMS LLC
  • EP2997390B1 patent drawingFigure 1~2
  • EP2997390B1 patent drawingFigure 2A
  • EP2997390B1 patent drawingFigure 2B

AI summary

A magnetic field sensor includes first, second, and third magnetic field sensing elements having respective first, second and third maximum response axes, the first second and third maximum response axes pointing along respective first, second, and third different coordinate axes. In response to a magnetic field, the first, second, and third magnetic field sensing elements are operable to generate first second, and third magnetic field signals. Signals representative of the first, second, and third magnetic field signals are compared with thresholds to determine if the magnetic field is greater than the thresholds. A corresponding method is also provided.