Hall Sensor Offset Compensation via Supply Modulation
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Solution Overview
Problem
Hall sensors exhibit a high, temperature-dependent offset portion in their output signal, which is difficult to compensate for, leading to time-consuming calibration processes and increased manufacturing costs, as existing methods like the spinning-current principle, orthogonal pair formation, and forced symmetry often leave residual temperature-dependent offsets.
Innovation Solution
A method involving modulation or variation of the supply signal to separate and eliminate the offset portion from the sensor output signal, using a fitting function to decompose the signal into useful and offset components, allowing for offset compensation without prior calibration or serial tests, by establishing a fitting function based on sensor signal values measured at different supply signal values within a constant magnetic field tolerance range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional offset compensation methods (spinning-current principle, orthogonal pair formation, forced symmetry) are used, then partial offset reduction is achieved, but residual temperature-dependent offset remains and time-consuming calibration is required
Solution Approach 1:
The patent applies parameter changes by modulating the supply voltage of the Hall sensor to different values (e.g., positive and negative supply voltages) to separate the offset signal from the useful signal. By measuring the sensor output at different supply voltage parameters and calculating the difference, the offset can be determined and compensated without time-consuming calibration processes.
Solution Approach 2:
The system performs self-service by automatically determining and compensating for its own offset during normal operation. The Hall sensor system measures its offset signal by modulating its own supply voltage and processing the resulting output signals, eliminating the need for external calibration equipment or manual calibration procedures.
2Ease of manufacture
If supply voltage modulation is used to determine offset, then offset compensation is achieved during operation without calibration, but the method requires constant magnetic field conditions within tolerance range
Solution Approach 1:
The patent applies preliminary action by performing offset determination at specific supply voltage conditions before normal measurement operations. The system pre-determines the offset by modulating the supply voltage and calculating the difference between measurements at different supply voltage levels, then uses this pre-determined offset for compensation during subsequent operations.
3Measurement precision
If multiple sensor signal values are established at different supply signal values, then accurate fitting function can be created, but measurement process requires temporal succession with constant magnetic field
Solution Approach 1:
The patent applies periodic action by modulating the supply voltage in a periodic manner (switching between positive and negative supply voltages) to generate alternating offset and useful signals. This periodic modulation allows the system to separate and determine the offset component through mathematical processing of the periodically varying signals.
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
Enables efficient and precise offset compensation during operation, reducing the need for complex calibration and lowering manufacturing costs, while allowing for the differentiation of sensor and amplifier offset drifts, thereby improving system error recognition.
Implementation Method 1
a Hall sensor for detecting a component of a measuring magnetic field and for outputting a sensor signal S based on the detected component of the measuring magnetic field
Data Source
AI summary
A central idea of techniques herein is that by means of modulation or variation of the supply signal of a Hall sensor, the useful signal portion in the resulting sensor output signal can be separated from the offset portion during operation of the Hall sensor, with no previous calibration or previous serial tests. That course of the sensor output signal resulting from the modulation or variation of the supply signal can then be evaluated or decomposed relative to the components which can be attributed to the offset portion and the useful signal portion. Thus, the offset portion in the sensor output signal can be determined with no (or a negligibly small) external magnetic field applied or with an external magnetic field applied, in case the external magnetic field is constant within a tolerance range while determining the offset portion.