Magnetic Field Sensing Apparatus Using Time-Division Wheatstone Bridges
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Solution Overview
Problem
Conventional magnetic field sensing apparatuses require larger layouts, increasing manufacturing costs and limiting their application in small-sized devices like smartphones and drones, which need three-axial sensing capabilities.
Innovation Solution
The apparatus employs a configuration of first and second magnetoresistance units with distinct magnetic field sensing axes, electrically connected to form Wheatstone full bridges in different time periods to measure magnetic field components in three dimensions, allowing for smaller size and increased flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic field sensing apparatus uses anisotropic magnetoresistors under Wheatstone bridge framework, then magnetic field sensing capability is achieved, but layout area becomes larger and manufacturing costs increase
Solution Approach 1:
The sensing apparatus is divided into multiple magnetoresistance units (first and second units) with different magnetic field sensing axes. These units are arranged in specific spatial configurations and electrically connected to form Wheatstone full bridges, enabling three-dimensional magnetic field sensing through segmented functional modules rather than a single large-scale sensor structure.
Solution Approach 2:
The patent introduces spatial dimensionality by arranging magnetoresistance units with sensing axes oriented in different directions (first direction, second direction, and third direction perpendicular to the plane). This multi-dimensional arrangement allows the system to sense magnetic fields in three dimensions simultaneously, transforming a two-dimensional sensing limitation into a three-dimensional sensing capability without proportionally increasing the planar layout area.
2Adaptability or versatility
If conventional magnetic field sensing apparatus is designed for three-axial sensing, then three-dimensional magnetic field measurement is achieved, but device size increases
Solution Approach 1:
The magnetoresistance units serve multiple functions: they can be electrically connected in different configurations to form different Wheatstone full bridges for measuring magnetic field components in different directions. The same physical units can be switched between different measurement modes (first direction, second direction, third direction), making the device universally capable of three-axial sensing without requiring separate dedicated sensors for each axis.
Solution Approach 2:
The electrical connections between magnetoresistance units are dynamically reconfigurable through switching circuits that can connect the units in different configurations at different time periods. This dynamic reconfiguration allows the same hardware to adaptively measure magnetic field components in different directions, achieving three-dimensional sensing capability while maintaining a compact physical footprint.
3Adaptability or versatility
If multiple magnetoresistance units are arranged to measure magnetic field components in different directions, then three-dimensional sensing is achieved, but device complexity increases
Solution Approach 1:
Multiple magnetoresistance units are merged into integrated Wheatstone full bridge circuits, where the units are electrically connected in systematic configurations. The first and second magnetoresistance units are combined with the magnetic field sensing device to form unified measurement systems, reducing the complexity that would otherwise arise from treating each unit as a separate component.
Solution Approach 2:
The switching circuits periodically reconfigure the electrical connections between magnetoresistance units at different time periods to measure magnetic field components in different directions. This periodic switching approach simplifies the overall system design by using time-division multiplexing rather than requiring all measurement pathways to be simultaneously active, thereby reducing structural complexity while maintaining full three-dimensional sensing capability.
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 three-dimensional magnetic field measurement with a simplified structure, reducing size and manufacturing costs while enhancing application flexibility.
Implementation Method 1
an extension direction of the anisotropic magnetoresistor belonging to the first magnetoresistance units is parallel to the second direction, and an extension direction of the anisotropic magnetoresistor belonging to the second magnetoresistance units is parallel to the first direction
Data Source
AI summary
A magnetic field sensing apparatus including a plurality of first magnetoresistance units, a plurality of second magnetoresistance units, and a magnetic field sensing device is provided. Magnetic field sensing axes of the first and second magnetoresistance units are parallel to a first direction and a second direction respectively, and the first and second magnetoresistance units are disposed beside the magnetic field sensing device, which is configured to measure a magnetic field component in a third direction. The first and second magnetoresistance units are electrically connected to form at least one kind of Wheatstone full bridge in two different time periods to respectively measure magnetic field components in fourth and fifth directions and to cause this kind of Wheatstone full bridge to output two signals respectively corresponding to the magnetic field components in the fourth and fifth directions. The first direction to the fifth direction are different from each other.