Magnetic Sensor Linearity Correction via Hyperbolic Function Transformation
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Solution Overview
Problem
Magnetic sensors face significant linearity errors at larger magnetic field ranges, limiting their working range and accuracy, especially in applications requiring high precision or larger magnetic fields, due to the presence of high-order components in their output voltage signals.
Innovation Solution
A correction method that applies hyperbolic functions or their inverses to the output voltage signal of magnetic sensors to reduce linearity errors, allowing for larger magnetic field ranges without compromising sensitivity, and is suitable for real-time correction and various sensor types, including MTJ-based sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the magnetic field range is increased, then the sensor can detect larger magnetic fields, but the linearity error increases rapidly
Solution Approach 1:
The patent applies parameter transformation by using hyperbolic functions (sinh, tanh, arctanh) to transform the output voltage signal. This mathematical transformation changes the parameter representation of the magnetic field response, converting the non-linear relationship into a more linear one, thereby reducing linearity error while maintaining extended magnetic field range capability
Solution Approach 2:
The patent introduces an intermediary correction circuit that processes the raw output voltage signal through hyperbolic function transformation. This intermediary stage acts as a mediator between the sensor output and the final measurement, applying the mathematical correction to reduce linearity error before the signal is used for measurement
2Measurement precision
If piece-wise linear correction is applied, then linearity is improved in segmented ranges, but device complexity increases
Solution Approach 1:
The patent merges multiple correction approaches into a single unified hyperbolic function transformation. Instead of using separate correction circuits for different magnetic field ranges (piece-wise approach), the invention combines the correction into one continuous mathematical function that works across the entire extended magnetic field range, thereby reducing device complexity while maintaining linearity improvement
3Measurement precision
If continuous compensation of high order terms is applied, then linearity is improved, but power consumption increases
Solution Approach 1:
The patent replaces complex continuous compensation circuits with a mathematical transformation approach usinghyperbolic functions. This substitution eliminates the need for additional active compensation components and continuous adjustment mechanisms, thereby reducing power consumption while achieving comparable or superior linearity improvement through the inherent properties of thehyperbolic function transformation
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 method effectively corrects non-linearity errors, enabling magnetic sensors to maintain high sensitivity and accuracy across larger magnetic field ranges, with improved robustness against variations in temperature and voltage, and reduces the need for individual calibration, thus enhancing manufacturing efficiency and reliability.
Implementation Method 1
Linear magnetic sensors have many consumer, industrial and automotive applications... Sensor technologies using Magnetic Tunnel Junctions (MTJs) based on Tunnel Magneto-Resistance (TMR) effect
Data Source
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AI summary
The present disclosure concerns a correction method for correcting an output voltage signal provided by a magnetic sensor, comprising: providing a sensor, comprising at least a magnetoresistive element, inputting the sensor by a bias voltage in the presence of the external magnetic field vector such that the sensor generates the output voltage signal; and determining a corrected output voltage signal from the output voltage signal, where the corrected output voltage signal has a linearity error smaller than the linearity error of the output voltage signal. The corrected output voltage signal is determined by applying a hyperbolic function or an inverse hyperbolic function or a combination of a hyperbolic function or an inverse hyperbolic function, to a signal proportional to the output voltage signal, or to an additional voltage signal being added or subtracted to the output voltage signal.