Vertical Hall Sensor Offset Reduction via Circular Signal Sequencing
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Solution Overview
Problem
Existing magnetic field sensors using vertical Hall elements face challenges in achieving high angular accuracy and speed, particularly due to offset errors and temperature sensitivity, which affect the reliability of angle sensing applications.
Innovation Solution
A magnetic field sensor design that combines the output signals from multiple vertical Hall elements using a sequence switches circuit and current switches circuit to generate constructive or compensating signals, reducing offset errors and enhancing angular accuracy and speed by sequentially selecting and combining the signals from vertically arranged Hall elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple vertical Hall elements are combined to improve angular accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Multiple vertical Hall elements are combined in a circular arrangement with their output signals processed through switching circuits to achieve offset cancellation. The signals from multiple elements are merged through sequential switching and algebraic combination to produce an output with reduced offset error, improving angular measurement precision while managing the complexity through systematic signal processing.
Solution Approach 2:
Switching circuits serve as intermediary components that sequentially connect different Hall elements to the output. These circuits mediate between the multiple Hall elements and the final output, enabling offset cancellation through controlled signal combination without requiring all elements to be permanently connected, thus managing device complexity.
2Measurement precision
If vertical Hall elements are used to detect magnetic field direction, then sensitivity to magnetic field is improved, but offset error increases
Solution Approach 1:
The offset errors generated by individual vertical Hall elements are converted into a beneficial cancellation effect. By arranging elements in a circular configuration and processing their signals through switching circuits that perform algebraic combination, the harmful offset errors are transformed into a system where errors cancel each other out, improving overall measurement accuracy.
Solution Approach 2:
The sensing function is segmented across multiple vertical Hall elements arranged in a circle, with each element contributing to the overall measurement. The switching circuits segment the signal processing into sequential steps, selecting and combining signals from different elements to achieve offset cancellation while maintaining sensitivity to the magnetic field direction.
3Measurement precision
If sequential switching of Hall elements is implemented to reduce offset, then measurement precision is improved, but speed of response decreases
Solution Approach 1:
The switching circuit operates periodically, sequentially connecting different Hall elements to the output in a repeating cycle. This periodic switching enables offset cancellation through systematic signal combination while maintaining a predictable response rate. The periodic nature allows the system to achieve precision through multiple measurements while providing a defined response speed based on the switching frequency.
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 offset errors and improves the angular accuracy and speed of magnetic field sensing, enabling more precise and rapid detection of magnetic field angles, even under varying temperature conditions.
Implementation Method 1
A plurality of vertical Hall elements arranged in a circle and formed as a corresponding plurality of sets of contacts among a plurality of contacts disposed upon a substrate. The plurality of vertical Hall elements generates a corresponding plurality of vertical Hall element output signals. Each one of the vertical Hall elements is responsive to an external magnetic field having an external magnetic field direction.
Data Source
Figure 1~1A
Figure 2
Figure 3
AI summary
Output signals from two or more vertical Hall elements arranged in a circle are combined is ways that reduce an offset voltage as the two or more vertical Hall elements are sequenced to generated a sequential output signal.