Hall Sensor Thermal Drift Control via Gate Electrode
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Solution Overview
Problem
Hall sensors in electricity meters face challenges with temperature-dependent magnetic sensitivity, leading to signal drift and instability, particularly in varying thermal environments, which affects the accuracy of measured data.
Innovation Solution
A methodology and apparatus that utilize a planar semiconductive Hall sensor with a gate electrode covering a portion of the active area, allowing for control of thermal drift by varying the gate electrode characteristics or applying a gate current, enabling the annulment of thermal effects on magnetic sensitivity, thereby improving data reliability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall sensor is used to measure magnetic fields in electricity meters, then measurement capability is provided, but temperature-dependent magnetic sensitivity causes signal drift and measurement precision degradation
Solution Approach 1:
The patent applies parameter changes by modifying the physical state of the Hall sensor through thermal treatment during fabrication. The sensor is heated to a specific temperature (e.g., annealing temperature) and then cooled to establish a predetermined relationship between carrier concentration and temperature. This pre-established relationship compensates for temperature-dependent drift during operation, maintaining measurement precision across varying temperatures without requiring active temperature compensation circuits.
2Adaptability or versatility
If electronic metrology devices are introduced to provide sophisticated usage data, then monitoring capability is improved, but thermal sensitivity of components increases and reliability decreases in hostile environments
Solution Approach 1:
The patent implements preliminary action by pre-compensating for thermal effects during the fabrication process rather than during operation. The Hall sensor undergoes thermal treatment (annealing) at a controlled temperature to establish a predetermined carrier concentration-temperature relationship before the device is deployed. This preliminary adjustment ensures that the sensor maintains stable magnetic sensitivity across the expected operating temperature range, enabling reliable electronic monitoring in thermally hostile environments without requiring complex active compensation systems.
3Measurement precision
If the active area of the Hall sensor is increased to improve signal strength, then measurement capability is enhanced, but temperature drift effects are amplified
Solution Approach 1:
The patent resolves this contradiction by changing the physical parameters of the Hall sensor through thermal annealing. By heating the sensor to a predetermined temperature and then cooling it, the carrier concentration distribution is modified to establish a compensatory relationship with temperature variations. This allows the sensor to maintain stable magnetic sensitivity even with a larger active area that provides stronger signals, as the pre-established parameter relationship counteracts the amplified temperature drift effects.
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 solution effectively reduces temperature-related signal errors and enhances the stability and reliability of Hall sensor data, making it suitable for diverse thermal environments and operational conditions.
Implementation Method 1
a gate electrode coupled to and covering at least a fractional portion of the central magnetic field responsive active area portion
Implementation Method 2
a Hall sensor is a device with at least four contacting electrodes. When biased with a current (Ibias) through two of such electrodes, a Hall sensor delivers between its other two electrodes a voltage that is proportional both to the component of the magnetic field perpendicular to the current trajectory
Data Source
AI summary
Disclosed are apparatus and methodology for providing approaches to remove or reduce thermal drift of the magnetic sensitivity of Hall sensor devices, to improve the stability of resulting signals of interest. Samples of a particular signal or signals of interest having improved stability make for advantageous use in conjunction with electricity meters. At the same time, associated designs and related components have greater simplicity, for reduced complexity in implementation. Among alternative embodiments, a gating structure selected of various present alternative designs may be used to partially cover, to an intentionally selected degree, an active area of a Hall sensor, so that a zero-drift supply current value may likewise be selected so as to satisfy other criteria which may be applicable to use of the Hall sensor. In other alternative embodiments, a gate structure is used which fully covers the Hall sensor active area, but a gate-control technique is practiced which is based on combined use with an external, relatively high resistance voltage-divider circuitry arrangement, again for eliminating temperature-based drift of the magnetic sensitivity of the Hall sensor arrangement, regardless of the end use to which such Hall sensor is applied.