CVH Sensor Angular Resolution via Parallel Signal Processing
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Solution Overview
Problem
Conventional magnetic field sensors using circular vertical Hall (CVH) sensing elements face limitations in achieving high angular resolution without increasing processing time, as they typically require sequential output signals from multiple vertical Hall elements.
Innovation Solution
A magnetic field sensor design that includes a semiconductor substrate with a CVH sensing element comprising multiple vertical Hall elements, an angle sensing circuit, a pole pair counting module, and an angle interpolation module, which generates an interpolated signal representing the position of a multi-pole magnet with enhanced resolution without additional time, utilizing a multiplexer, comparator, and counter to combine and process signals from the CVH output and clock signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If output signals from vertical Hall elements are generated sequentially, then device complexity is reduced, but measurement precision and productivity deteriorate
Solution Approach 1:
The patent divides the circular vertical Hall sensing element into multiple vertical Hall elements (first, second, third, and fourth VHEs) arranged at different angular positions around a common implant region. Each VHE generates output signals independently, allowing parallel processing of magnetic field information from different directions, thereby improving angular resolution without proportionally increasing overall device complexity
Solution Approach 2:
The patent combines output signals from multiple vertical Hall elements through signal processing circuits that integrate the signals to determine magnetic field direction. By merging the output signals from multiple VHEs simultaneously, the system achieves high angular resolution measurement without requiring sequential processing, thus maintaining both measurement precision and productivity
2Measurement precision
If all output signals from vertical Hall elements are processed to determine magnetic field direction, then measurement precision improves, but productivity deteriorates
Solution Approach 1:
The patent employs offset compensation circuits that pre-process the output signals from vertical Hall elements by detecting and compensating for offset errors before the main signal processing. This preliminary action ensures that all signals are ready for simultaneous processing, enabling high-speed determination of magnetic field direction without sacrificing measurement precision
Solution Approach 2:
The patent enables continuous simultaneous processing of output signals from all vertical Hall elements through parallel signal processing paths. All VHEs operate continuously and their signals are processed concurrently, eliminating idle time and ensuring continuous useful action, thereby maintaining both high angular resolution and fast signal generation speed
3Measurement precision
If offset compensation is performed for each vertical Hall element, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent implements a universal offset compensation approach where the same compensation circuit architecture is applied to all vertical Hall elements. The offset compensation circuits use identical methodologies and structures for each VHE, allowing standardized processing that reduces overall system complexity while maintaining high signal accuracy across all elements
Solution Approach 2:
The patent adjusts operational parameters such as current direction and signal polarity to facilitate offset compensation. By changing the excitation current direction through the vertical Hall elements and accordingly adjusting the signal processing parameters, the system achieves accurate offset compensation without requiring complex additional circuitry for each element
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 design enables a more accurate and precise determination of the position of a multi-pole magnet with higher angular resolution, avoiding phase differences between circuit channels and providing improved positional sensing without increasing processing time.
Implementation Method 1
A vertical Hall element tends to be responsive to magnetic field parallel to a surface of a substrate on which the vertical Hall element is formed
Data Source
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AI summary
A magnetic field sensor has a circular vertical Hall (CVH) sensing element with a plurality of vertical Hall elements disposed over a common implant region in a substrate. The plurality of vertical Hall elements is disposed in an x-y plane. The magnetic field sensor is responsive to a magnetic field generated by a multi-pole magnet having a plurality of north poles and also a plurality of south poles arranged in a plane parallel to the x-y plane, and, in some embodiments, arranged in the x-y plane. A corresponding method is also described.