Magnetic Field Sensing Apparatus with Time Division Switching

Solution Overview

Problem

The manufacturing of magnetic field sensing apparatuses with multiple pinning directions for three-axis sensing is complex and costly, leading to reduced stability and increased volume due to the need for precise alignment of antiferromagnetic layers.

Innovation Solution

A magnetic field sensing apparatus with single direction magneto-resistive sensors and a time division switching circuit, where sensors are positioned beside the corners of a magnetic flux concentrator, allowing for different Wheatstone bridges to be formed in various time intervals to measure magnetic field components in different directions, simplifying manufacturing and reducing costs while maintaining stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple pinning directions are designed on an antiferromagnetic layer for three-axis sensing, then three-axis sensing capability is achieved, but manufacturing complexity increases and production costs rise

Engineering Contradiction:

Improvethree-axis sensing capabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs time-division switching to dynamically reconfigure the sensing circuit. A single set of magneto-resistive sensors with unified pinning direction is sequentially connected to form different Wheatstone bridges for measuring magnetic fields along x, y, and z axes at different time intervals. This dynamic reconfiguration replaces the static complex multi-directional pinning structure, achieving three-axis sensing capability while simplifying manufacturing.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent makes a single set of magneto-resistive sensors serve multiple functions by using time-division multiplexing. The same sensors are sequentially allocated to measure magnetic field components along different axes, allowing one sensor array to perform the work that would traditionally require multiple sensor arrays with different pinning directions, thereby reducing manufacturing complexity and cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple pinning directions are designed on an antiferromagnetic layer for three-axis sensing, then three-axis sensing capability is achieved, but production costs increase

Engineering Contradiction:

Improvethree-axis sensing capabilityVSAvoidproduction cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent employs time-division switching to dynamically reconfigure the sensing circuit. A single set of magneto-resistive sensors with unified pinning direction is sequentially connected to form different Wheatstone bridges for measuring magnetic fields along x, y, and z axes at different time intervals. This dynamic reconfiguration replaces the static complex multi-directional pinning structure, achieving three-axis sensing capability while simplifying manufacturing.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Instead of physically creating multiple sets of sensors with different pinning directions, the patent uses electrical switching to create virtual copies of the sensing function. The time-division switching circuit electronically reconfigures the same physical sensors to perform measurements in different spatial directions, eliminating the need for expensive multi-directional pinning layer fabrication.

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If multiple pinning directions are designed on an antiferromagnetic layer for three-axis sensing, then three-axis sensing capability is achieved, but stability of pinning layer decreases

Engineering Contradiction:

Improvethree-axis sensing capabilityVSAvoidstability of pinning layer

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs time-division switching to dynamically reconfigure the sensing circuit. A single set of magneto-resistive sensors with unified pinning direction is sequentially connected to form different Wheatstone bridges for measuring magnetic fields along x, y, and z axes at different time intervals. This dynamic reconfiguration replaces the static complex multi-directional pinning structure, achieving three-axis sensing capability while simplifying manufacturing.

Inventive Principle:

Principle #15Dynamics

4Device complexity

If single direction magneto-resistive sensors with time division switching are used, then manufacturing complexity is reduced and cost decreases, but device volume may increase due to switching circuit

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddevice volume

Core Design Contradiction:

Device complexityVSVolume of stationary object

Solution Approach 1:

The patent combines the magneto-resistive sensors and the time-division switching circuit into an integrated structure. The switching circuit is closely coupled with the sensor array, allowing the sensing elements and control circuitry to share space and resources. This merging reduces the overall device volume despite the added switching functionality, while maintaining manufacturing simplicity.

Inventive Principle:

Principle #5Merging (Combining)

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 configuration enables efficient three-axis sensing with a simpler manufacturing process, lower production costs, and improved stability, while the compact design allows the Wheatstone bridges to span the magnetic flux concentrator, resulting in a smaller volume.

Implementation Method 1

a giant magnetoresistance (GMR) multilayer film structure or a tunneling magnetoresistance (TMR) multilayer film structure may generally used to constitute a Wheatstone full bridge

Methodology Applied

Scientific EffectGiant magnetoresistance (GMR): Magnetoresistance

Implementation Method 2

a giant magnetoresistance (GMR) multilayer film structure or a tunneling magnetoresistance (TMR) multilayer film structure may generally used to constitute a Wheatstone full bridge

Methodology Applied

Scientific EffectTunneling magnetoresistance (TMR): Magnetoresistance

Implementation Method 3

The magnetic flux concentrator has a plurality of corners. The single direction magneto-resistive sensors are respectively disposed beside the corners

Methodology Applied

Scientific EffectMagnetic flux concentration: Magnetic Field

Implementation Method 4

form different Wheatstone bridges in different time intervals to measure magnetic field components of an external magnetic field in different directions

Methodology Applied

Scientific EffectWheatstone bridge: Wheatstone Bridge

Data Source

PatentUS11237229B2Magnetic field sensing apparatus

Publication Date: 2022.02.01 ISENTEK INC

AI summary

A magnetic field sensing apparatus including a magnetic flux concentrator, a plurality of single direction magneto-resistive sensors and a time division switching circuit is provided. The magnetic flux concentrator has a plurality of corners. The single direction magneto-resistive sensors have a same pinning direction. The single direction magneto-resistive sensors are respectively disposed beside the corners. The time division switching circuit is coupled to the single direction magneto-resistive sensors, and is configured to switch at least a portion of the junctions between the single direction magneto-resistive sensors to change a circuit connection between the magneto-resistive sensors, thereby forming different Wheatstone bridges being configured to measure different magnetic field components of the external magnetic field in different directions.