Rotation Angle Detector Serial Hall Drive Circuit
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Solution Overview
Problem
Conventional rotation angle detectors using hall elements are prone to accidental errors due to variations in temperature and electric source changes, which affect the signal ratio and accuracy of rotation angle detection.
Innovation Solution
The rotation angle detector serially connects multiple hall elements and applies equal drive currents to them, allowing for external adjustment of signal gain to maintain constant signal ratios and optimize signal amplitudes, thereby reducing the impact of temperature and electric source variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate drive circuits with individual resistances are used for each hall element, then each hall element can be driven independently, but strictly equal current values cannot be applied due to resistance variations and temperature effects
Solution Approach 1:
The patent merges separate drive circuits into a single common drive circuit that supplies equal currents to multiple hall elements. By using a shared current source with equal resistance connections, the system ensures that all hall elements receive identical drive currents regardless of individual component variations or temperature effects, thereby maintaining constant signal ratios and improving measurement precision.
2Measurement precision
If temperature compensation elements such as thermistors are added, then temperature effects can be compensated, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates temperature compensation elements (thermistors) from the system by redesigning the drive circuit architecture. Instead of adding compensation components, the invention uses a symmetric common drive circuit where temperature effects naturally cancel out due to equal current distribution, thereby maintaining measurement precision while reducing device complexity.
3Measurement precision
If signal gain adjustment is added to optimize signal amplitudes, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent implements a universal common drive circuit that serves multiple functions: it provides equal current distribution to all hall elements, maintains constant signal ratios, and enables external signal gain adjustment. By making the drive circuit multi-functional, the system achieves improved detection accuracy without proportionally increasing device complexity, as the same circuit structure accomplishes multiple objectives.
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 ensures accurate rotation angle detection by maintaining equal signal outputs from hall elements, reducing measurement errors caused by temperature and electric source changes, and optimizing signal processing for improved resolution and accuracy.
Implementation Method 1
a magnet (12) fixed to the rotator (11) and plural magnetic detection means (13a, 13b) for detecting strength of the magnet
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Since a drive circuit (20) in which Hall elements (13a, 13b) are connected in series is provided in a rotation sensor (10), the same drive current I can be fed to the Hall elements (13a, 13b). Since a disturbance such as temperature variation or power supply variation has the same impact on the Hall elements (13a, 13b), signal ratio of output signals from the Hall elements (13a, 13b) can be made constant.