Complementary Coil Hall Sensor Layout for Process-Variation Calibration
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Solution Overview
Problem
Existing Hall effect sensors face challenges in accurately measuring magnetic fields due to manufacturing variations and process-related deviations, which complicate the calibration and trimming processes, leading to reduced fidelity and accuracy in magnetic field strength measurements.
Innovation Solution
A multiple coil design is employed, comprising a larger primary coil with a specific set of correlation coefficients and smaller secondary coils, strategically positioned and sized to achieve a 1:1 correlation coefficient ratio, enabling accurate Hall element response to both on-chip and uniform magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coil is used for Hall sensor calibration, then the device complexity is reduced, but the measurement precision and calibration accuracy deteriorate due to manufacturing variations and process deviations
Solution Approach 1:
The patent divides the single coil system into multiple segmented coils (first coil, second coil, third coil, fourth coil) arranged in a complementary configuration. Each coil contributes to generating a composite magnetic field that compensates for manufacturing variations, thereby improving measurement precision while maintaining manageable device complexity through modular segmentation.
Solution Approach 2:
The patent employs parameter changes by adjusting the correlation coefficients of different coils to achieve a 1:1 ratio. This involves modifying the electrical parameters (current, turns, area) of each coil to optimize the composite magnetic field generation, thereby improving calibration accuracy and measurement precision without significantly increasing overall system complexity.
2Measurement precision
If manufacturing variations are reduced to improve calibration accuracy, then the measurement precision improves, but the manufacturing cost and process complexity increase
Solution Approach 1:
The complementary coil system performs self-calibration by generating a composite magnetic field that inherently compensates for manufacturing variations. The system uses its own multiple coils to create reference fields for calibration, eliminating the need for external calibration equipment and complex external calibration processes, thereby improving calibration accuracy while maintaining ease of manufacture.
Solution Approach 2:
The patent uses parameter changes in the coil design (correlation coefficients, turn ratios, areas) to create a system that is inherently robust to manufacturing variations. By designing the coils with specific parameter relationships (1:1 correlation coefficient ratio), the system automatically compensates for process deviations, improving calibration accuracy without requiring tighter manufacturing tolerances.
3Measurement precision
If a complementary multi-coil system is implemented, then the calibration accuracy and measurement fidelity improve, but the device complexity and area increase
Solution Approach 1:
The patent merges multiple coils into a unified complementary coil system where the first, second, third, and fourth coils work together to generate a composite magnetic field. This merging approach improves calibration fidelity by combining the effects of multiple coils while maintaining a structured, organized configuration that manages device complexity through systematic integration.
Solution Approach 2:
The complementary coil system serves multiple functions: it generates reference magnetic fields for calibration, compensates for manufacturing variations, and provides robust measurement capability across different operating conditions. This multi-functionality improves calibration fidelity while justifying the increased device complexity through the system's versatile capabilities.
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 enhances the accuracy of Hall element calibration and robustness across process variations, improving the fidelity and precision of magnetic field strength measurements.
Implementation Method 1
Hall effect sensors use a voltage caused by a Lorentz force exerted by a magnetic field (or B-field) on electrons in a current flowing through a conductor to detect and measure a component of the magnetic field that is perpendicular to the current flow
Implementation Method 2
Hall effect sensors use a voltage caused by a Lorentz force exerted by a magnetic field
Implementation Method 3
A magnetic concentrator, a Hall sensor, a primary coil, and a secondary coil are provided. The Hall sensor at least partially overlaps the magnetic concentrator
Implementation Method 4
A multiple coil design is employed, comprising a larger primary coil with a specific set of correlation coefficients and smaller secondary coils, strategically positioned and sized to achieve a 1:1 correlation coefficient ratio
Data Source
AI summary
In described examples, an integrated circuit (IC) written on a substrate that includes a substrate surface includes a magnetic concentrator, a Hall sensor, a primary coil, and a secondary coil. The Hall sensor at least partially overlaps the magnetic concentrator. The primary coil at least partially overlaps the magnetic concentrator. The secondary coil at least partially overlaps the magnetic concentrator and the primary coil, and surrounds the Hall sensor.