AMR Sensor Layout Reduction via Merged Resistors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional magnetic field sensing apparatuses using anisotropic magneto-resistive (AMR) resistors in a Wheatstone bridge configuration require a large layout area, increasing production costs and limiting their application in small portable devices and drones.
Innovation Solution
A magnetic field sensing apparatus utilizing two AMR resistors with opposite or same magnetized directions, coupled with a current generator and arithmetic device, where the resistances of the AMR resistors vary inversely with the magnetic field, allowing for reduced circuit layout area and improved accuracy through arithmetic operations on detection voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Wheatstone full bridge configuration with four AMR resistors is used, then the magnetic field sensing accuracy is improved, but the layout area increases
Solution Approach 1:
The patent combines the functions of four AMR resistors into a single AMR resistor by integrating both X-axis and Y-axis sensing capabilities within one resistor structure. This merging approach maintains the accuracy benefits of a full bridge configuration while reducing the layout area to that of a single resistor, directly resolving the contradiction between sensing accuracy and area occupation.
Solution Approach 2:
The single AMR resistor is designed to perform multiple sensing functions simultaneously - it can detect both X-axis and Y-axis magnetic field components. This multi-functionality allows the system to achieve the measurement precision of a four-resistor configuration while using only one physical resistor, thereby reducing the layout area.
2Adaptability or versatility
If four AMR resistors are used in a Wheatstone full bridge configuration, then the sensing function is improved, but the production cost increases
Solution Approach 1:
The patent merges the sensing functions of four separate AMR resistors into a single integrated resistor structure. This reduction from four components to one component directly lowers production costs by reducing material usage, assembly steps, and manufacturing complexity, while maintaining the full sensing functionality through the multi-axis detection capability of the single resistor.
3Adaptability or versatility
If four AMR resistors are used, then the 3-axis sensing capability is achieved, but the volume of the apparatus increases
Solution Approach 1:
The patent combines multiple sensing functions into a single AMR resistor, enabling 3-axis sensing capability (X-axis and Y-axis detection) while reducing the apparatus volume. The single-resistor design eliminates the need for four separate component packages and their associated mounting space, directly addressing the volume reduction requirement for portable devices.
Solution Approach 2:
The patent utilizes the anisotropic magneto-resistive effect to detect magnetic fields in multiple dimensions (X-axis and Y-axis) using a single resistor structure. By leveraging the directional sensitivity of the AMR effect, the system achieves multi-axis sensing capability without proportionally increasing the physical volume, as the multi-detection capability is embedded in the material's physical properties rather than requiring additional spatial dimensions.
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 effectively reduces the volume and production costs of magnetic field sensing apparatuses while enhancing accuracy by compensating for system offsets and ambient noise, improving the sensing of magnetic fields in small portable devices and drones.
Implementation Method 1
anisotropic magneto-resistive (AMR) resistors are frequently used to sense the magnetic field
Data Source
AI summary
A magnetic field sensing apparatus and a detection method thereof are provided. The magnetic field sensing apparatus includes first and second AMR resistors, a current generator, and an arithmetic device. A magnetized direction of the first AMR resistor is set as a first direction. A magnetized direction of the second AMR resistor is set as a second direction opposite to or the same as the first direction. The current generator provides a current in a direction parallel to the first direction to flow through the first and second AMR resistors. The arithmetic device obtains a first detection voltage according to a voltage difference between two terminals of the first AMR resistor, obtains a second detection voltage according to a voltage difference between two terminals of the second AMR resistor, and performs his an arithmetic operation on the first and second detection voltages to obtain a first magnetic field detection result.