Magnetic Field Sensor Single Planar Strap Offset Compensation
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Solution Overview
Problem
The complexity and increased manufacturing cost of magnetic-field sensors with anisotropic magnetoresistive elements due to the need for multiple straps and metal levels complicate the fabrication process and reduce sensitivity due to offset signals.
Innovation Solution
A magnetic-field sensor design that integrates a single planar conductive strip for both set/reset and calibration/offset compensation operations, eliminating the need for separate straps and reducing the number of metal levels, thereby simplifying the fabrication process and enhancing sensitivity by using a single metal level for the magnetic-field generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate set/reset strap and offset strap are used, then the sensor can perform set/reset and calibration operations, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the set/reset strap and offset strap into a single integrated strap structure. This single strap performs both set/reset operations and calibration/offset compensation operations by applying currents in different directions and modes, thereby reducing the number of separate components while maintaining full sensor functionality.
Solution Approach 2:
The integrated strap is designed to serve multiple functions: it can perform set operations, reset operations, calibration operations, and offset compensation operations. By making the strap multi-functional, the patent eliminates the need for separate dedicated straps for each function, simplifying the overall device structure.
2Adaptability or versatility
If multiple metal levels are used for straps, then the sensor can implement complex strap configurations, but the manufacturing process becomes more complex and costly
Solution Approach 1:
Instead of using multiple metal levels (vertical dimension) to create separate straps, the patent implements the integrated strap configuration within a single metal level by utilizing planar geometry and strategic positioning. This approach maintains the necessary strap configurations while avoiding the complexity of multi-level metal stacking and associated fabrication processes.
3Adaptability or versatility
If separate straps are used for set/reset and offset compensation, then the sensor can perform specialized operations, but offset signals reduce sensitivity
Solution Approach 1:
By merging the set/reset strap and offset strap into a single integrated structure, the patent enables more precise control and matching of the magnetic field generation. This integration allows for better compensation of offset signals while maintaining specialized operational capabilities, thereby improving sensor sensitivity without sacrificing functional versatility.
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 design simplifies the fabrication process, reduces manufacturing costs, and improves sensitivity by eliminating offset signals, making the sensor more efficient and cost-effective.
Implementation Method 1
the phenomenon of anisotropic magnetoresistivity occurs within particular ferromagnetic materials, which, when subjected to an external magnetic field, undergo a variation of resistivity as a function of the characteristics of the magnetic field applied
Implementation Method 2
the set/reset strap has the function of varying, alternating it, the sense of magnetization of the magnetoresistive elements in a first pre-defined direction (the so-called 'easy axis' or EA)
Implementation Method 3
The magnetic field generated by the offset strap is such as to force partially the orientation of the magnetic dipoles of each magnetoresistive element in a second pre-defined direction (the so-called 'hard axis' or HA), orthogonal to the first pre-defined direction
Data Source
AI summary
An integrated magnetic-field sensor designed to detect an external magnetic field, comprising a first magnetoresistive structure for detecting the external magnetic field, the first magnetoresistive structure including first magnetoresistive means having a main axis of magnetization and a secondary axis of magnetization set orthogonal to one another. The magnetic-field sensor further comprises a magnetic-field generator, including a first portion configured for generating a first magnetic field having field lines in a first field direction, and a second portion, which is coplanar and is connected to the first portion, configured for generating a second magnetic field having field lines in a second field direction, the first magnetoresistive means being configured so that the main axis of magnetization extends parallel to the first field direction, and the secondary axis of magnetization extends parallel to the second field direction.