Position Detecting Circuit Temperature Compensation Hall Effect
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Solution Overview
Problem
Sensor systems using permanent magnets and Hall effect devices face reduced sensitivity and accuracy due to temperature changes, affecting position detection between objects.
Innovation Solution
A position detecting circuit with multiple magnetic field detecting devices, a correction parameter arithmetic section, and a position arithmetic section that computes and outputs relative position based on output differences and correction parameters, stabilizing the sum of outputs to a constant value, thereby compensating for temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Hall effect devices are used for position detection, then the system cost is reduced, but the position detection accuracy deteriorates with temperature change
Solution Approach 1:
The patent applies parameter changes by utilizing the temperature characteristics of transistors to dynamically adjust the drive current through voltage dividing resistors and regulating resistors. This compensates for the Hall effect device's sensitivity changes with temperature, maintaining position detection accuracy while keeping the system cost-effective
Solution Approach 2:
The patent implements feedback by using transistors with opposite temperature characteristics to the Hall effect device. The transistor's temperature response feeds back to adjust the drive current, counteracting the Hall effect device's temperature-induced sensitivity changes and stabilizing position detection accuracy
2Measurement precision
If correction means is added to compensate for temperature characteristics, then position detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the temperature compensation function into the existing position detection circuit by integrating transistors, voltage dividing resistors, and regulating resistors directly with the Hall effect device. This combined approach achieves temperature compensation without adding separate complex correction systems
Solution Approach 2:
The patent applies self-service by utilizing the inherent opposite temperature characteristics of transistors to automatically compensate for Hall effect device drift. The circuit self-regulates through the transistor's temperature response, eliminating the need for external temperature sensors or complex correction algorithms
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 solution enhances the accuracy and linearity of position detection by normalizing output signals, reducing errors caused by individual magnet variance and temperature characteristics, allowing for high-precision position detection without requiring correction parameters for each individual device.
Implementation Method 1
sensor systems using a permanent magnet and Hall effect device (magnetic field detecting device)
Data Source
AI summary
A position detecting circuit including: a plurality of magnetic field detecting devices discretely disposed for outputting a signal corresponding to a magnetic field strength produced by an oppositely disposed magnetic field generation means; a correction parameter arithmetic section for computing correction parameters for bringing to a predetermined constant value a sum of output from one of the magnetic field detecting devices and an output from another of the magnetic field detecting devices; and a position arithmetic section for computing and outputting a relative position between the magnetic field generation means and the magnetic field detecting devices based on an output difference the between the output from the one magnetic field detecting device and output from the another magnetic field detecting device and the correction parameters.