Hall Element Signal Calibration for Angle Sensor Error Reduction
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Solution Overview
Problem
Magnetic-field angle sensors experience increased angle error due to improper calibration of Hall elements, leading to inaccuracies in measuring the angular position of rotating magnets.
Innovation Solution
The implementation of a dual Hall element configuration with orthogonal axes and calibration circuitry that generates compensation signals based on measured magnetic flux densities to adjust external magnetic flux densities, thereby reducing angle error. This includes conducting calibration currents through conduction paths parallel to each axis to generate specific magnetic flux densities at each Hall element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall elements are not properly calibrated, then the angle sensor can operate without additional calibration circuitry, but angle error increases leading to measurement inaccuracy
Solution Approach 1:
The calibration circuitry is integrated into the angle sensor device itself, merging the calibration function with the measurement function. This allows the sensor to perform self-calibration using on-chip resources including the Hall elements, conduction paths, and compensation signal generation circuits, eliminating the need for external calibration equipment while maintaining measurement accuracy
Solution Approach 2:
The calibration process is performed preliminarily during device operation or manufacturing, establishing accurate measurement parameters before normal angle sensing begins. The calibration circuitry pre-determines compensation values that are stored and applied during subsequent measurements, ensuring high accuracy from the start of operation
2Measurement precision
If calibration currents are conducted through conduction paths to generate magnetic flux densities for calibration, then sensitivity mismatches can be compensated, but additional energy consumption occurs
Solution Approach 1:
Calibration currents are applied periodically or in discrete pulses rather than continuously, allowing the Hall elements to be calibrated at specific intervals while consuming minimal energy during normal operation. This periodic calibration approach maintains sensitivity matching without continuous energy expenditure
Solution Approach 2:
Calibration currents are applied only to specific Hall elements or conduction paths that require calibration, rather than energizing the entire sensor system continuously. This partial action approach applies energy only where and when needed, reducing overall energy consumption while achieving sufficient sensitivity matching
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 approach enhances the accuracy of magnetic-field angle sensors by compensating for sensitivity mismatches and harmonic errors, improving the overall angle measurement precision.
Implementation Method 1
a conduction path having a first portion extending parallel to the first axis and a second portion parallel to the second axis. The conduction path is configured to conduct a calibration current that generates a first magnetic flux density measured at the first Hall element and a second magnetic flux density measured at the second Hall element
Implementation Method 2
a first Hall element disposed on a first axis, a second Hall element disposed on a second axis perpendicular to the first axis
Data Source
AI summary
In one aspect, an angle sensor includes a first Hall element disposed on a first axis, a second Hall element disposed on a second axis perpendicular to the first axis and a conduction path having a first portion extending parallel to the first axis and a second portion parallel to the second axis. The conduction path is configured to conduct a calibration current that generates a first magnetic flux density measured at the first Hall element and a second magnetic flux density measured at the second Hall element. The angle sensor also includes calibration circuitry configured to generate one or more compensation signals based on the first and second magnetic flux densities and to adjust an external magnetic flux density measured at the second Hall element due to an external magnetic field using the one or more compensation signals to reduce angle error of the angle sensor.