Magnetoresistive Bridge Sensor with Selectable Operating Point
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Solution Overview
Problem
Conventional magnetoresistive sensors face challenges in shifting the magnetic and electrical operating points without compromising sensitivity, often requiring additional components like shift resistors that increase complexity and reduce accuracy.
Innovation Solution
A magnetoresistive magnetic field sensor is designed with four magnetoresistive elements in a Wheatstone bridge configuration, where each element has distinct initial conductance values, allowing the magnetic and electrical operating points to be shifted by selecting appropriate conductance values, eliminating the need for additional shift resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional shift resistors are used to shift the magnetic and electrical operating points, then the operating points can be adjusted, but the device complexity increases and measurement precision decreases
Solution Approach 1:
The patent removes the additional shift resistors from the conventional Wheatstone bridge circuit. By integrating the shift function directly into the magnetoresistive sensor elements themselves, the circuit is simplified while retaining the ability to adjust magnetic and electrical operating points. This extraction of unnecessary components directly reduces device complexity while maintaining adaptability.
Solution Approach 2:
The patent combines the operating point shifting function with the magnetoresistive sensor elements. Instead of using separate shift resistors, the sensor elements are designed to inherently provide both sensing and operating point adjustment functions. This merging eliminates additional components and reduces circuit complexity while preserving full adjustability of operating points.
2Adaptability or versatility
If additional shift resistors are used to shift the magnetic and electrical operating points, then the operating points can be adjusted, but measurement precision and accuracy are reduced
Solution Approach 1:
By removing the shift resistors from the circuit, the patent eliminates the additional error sources and noise that these components introduce. The measurement path is simplified, allowing for higher precision and accuracy in magnetic field detection while maintaining the ability to adjust operating points through the integrated sensor element design.
Solution Approach 2:
The integration of the shift function into the magnetoresistive sensor elements themselves ensures that the adjustment mechanism does not introduce additional measurement errors. The combined design maintains a cleaner signal path and reduces the number of interfaces where noise and errors could be introduced, thereby preserving measurement precision.
3Device complexity
If conventional magnetoresistive sensors are used with standard Wheatstone bridge configuration, then the circuit is simple, but the magnetic and electrical operating points cannot be shifted without additional components
Solution Approach 1:
The patent merges the operating point adjustment capability directly into the magnetoresistive sensor elements. This integration allows the standard Wheatstone bridge configuration to maintain its simplicity while gaining the ability to shift magnetic and electrical operating points. The sensor elements themselves provide the adjustment function, eliminating the need for additional external components.
Solution Approach 2:
The magnetoresistive sensor elements are designed to perform multiple functions: they serve as both the sensing elements and the operating point adjustment mechanism. This multi-functionality allows the circuit to remain simple while providing full adjustability of operating points, as the same components that detect magnetic fields also control the operating points.
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 precise control over operating points without sensitivity loss, simplifying the circuit and reducing potential defects, while maintaining high sensitivity and accuracy.
Implementation Method 1
A magnetoresistive magnetic field sensor comprises a plurality of magnetoresistive sensor elements, the conductance values or resistance values of which change in response to an external magnetic field present
Data Source
AI summary
Disclosed herein is a magnetoresistive magnetic field sensor which, inter alia, includes four magnetoresistive elements arranged in a Wheatstone full bridge circuit. A first magnetoresistive element and a second magnetoresistive element, which respectively have an inverse behavior in relation to a change in conductance, are arranged in a first half bridge. A third magnetoresistive element and a fourth magnetoresistive element, which respectively have an inverse behavior in relation to a change in conductance, are arranged in a second half bridge. At least two of the four magnetoresistive elements have different conductance values when no external magnetic field is present. In each case, two of the four magnetoresistive elements have the same conductance if an external magnetic field with a predefined magnetic field strength is present.