Linear Magnetoresistance Bridge for High Magnetic Field Sensing
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Solution Overview
Problem
Magnetic-field sensing elements, such as GMR and TMR elements, often exhibit non-linear responses to magnetic field trajectories, making it challenging to construct linear magnetometers that accurately detect horizontal magnetic field intensity values, especially in the presence of high magnetic fields or varying temperatures.
Innovation Solution
The use of bridges comprising specific configurations of magnetoresistance elements with determined reference angles, allowing for a linear response to horizontal magnetic field intensity values, even in the absence of external magnetic field biases, by compensating for non-linearity through strategically positioned MR elements with different reference directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetoresistance elements are used for magnetic field sensing, then sensitivity to magnetic field changes is improved, but non-linear response to magnetic field trajectories occurs
Solution Approach 1:
The bridge circuit divides the sensing function into four separate magnetoresistance elements, each experiencing different magnetic field conditions. By segmenting the measurement function across multiple elements with different orientations, the patent achieves linear overall response while maintaining high sensitivity through the individual nonlinear responses of each element.
Solution Approach 2:
The patent employs magnetoresistance elements with different reference angles (orientations) arranged in an asymmetric bridge configuration. This asymmetric arrangement with specific angle combinations (e.g., 0°, 45°, 90°, 135°) transforms the nonlinear individual responses into a linear composite response, resolving the contradiction between sensitivity and linearity.
2Measurement precision
If magnetoresistance elements with fixed reference angles are used, then sensitivity in specific directions is improved, but adaptability to varying magnetic field orientations deteriorates
Solution Approach 1:
The bridge circuit configuration enables the system to universally measure magnetic field components in multiple orientations simultaneously. By combining four magnetoresistance elements with different reference angles, the system achieves multi-functionality, capable of detecting horizontal and vertical field components regardless of their specific orientation, thus improving adaptability while maintaining directional sensitivity.
3Manufacturing precision
If conventional bridge configurations are used, then linear response is achieved, but accuracy in high magnetic field intensity regions deteriorates
Solution Approach 1:
The patent changes the reference angle parameter of the magnetoresistance elements to achieve linear response across extended dynamic ranges. By optimizing the angle combinations and adjusting the bridge configuration parameters, the system maintains both linearity and accuracy in high magnetic field regions, resolving the contradiction between linear response and high-field accuracy.
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 linear response over a range of horizontal magnetic field values, including high intensity regions, and maintains stability across varying temperatures, reducing dynamic resistance and temperature dependency, thus enhancing the accuracy and reliability of magnetic field sensing.
Implementation Method 1
a first magnetoresistance element having a first reference angle; a second magnetoresistance element in series with the first magnetoresistance element and having a second reference angle
Data Source
AI summary
In one aspect, a bridge includes a first magnetoresistance element having a first reference angle; a second magnetoresistance element in series with the first magnetoresistance element and having a second reference angle; a third magnetoresistance element in parallel with the first magnetoresistance element and having the first reference angle; and a fourth magnetoresistance element in series with the third magnetoresistance element and having the second reference angle. An output of the bridge has a linear response over a range of horizontal magnetic field values having non-zero values and the range of horizontal magnetic field intensity values are associated with vertical magnetic field intensity values having zero Oersted (Oe) values. A reference angle indicates an angle the magnetoresistance element is most sensitive to changes in a magnetic field.