Differential Magnetic Current Sensing Without Bulky Shields
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Solution Overview
Problem
Current sensors face challenges in accurately measuring fast-varying electrical currents due to induced voltages from high-frequency magnetic flux, leading to measurement errors and potential malfunctions, and the use of magnetic shields increases device footprint.
Innovation Solution
A magnetic field sensor with two sensing elements positioned to sense magnetic fields at specific angles and distances, using integrated magnetic concentrators and elongated leads to reduce electromagnetic interference, allowing for differential signal processing without large shields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic shields are used to reduce magnetic noise influence, then measurement precision is improved, but device footprint increases
Solution Approach 1:
The patent extracts the magnetic shielding function from a separate physical component and integrates it into the sensor substrate itself. The substrate is designed with magnetic shielding properties that directly protect the sensing elements, eliminating the need for additional external shield structures and reducing overall device footprint while maintaining noise rejection capability.
Solution Approach 2:
The patent merges multiple functions into the sensor substrate: the substrate serves both as the mechanical support for sensing elements and as the magnetic shielding structure. This integration combines the structural support function with the electromagnetic protection function, reducing the number of separate components needed.
2Measurement precision
If traditional single sensing element configuration is used, then device complexity is reduced, but measurement precision deteriorates due to induced voltages from high-frequency currents
Solution Approach 1:
The patent divides the sensing function into multiple sensing elements arranged in a specific pattern on the substrate. This segmentation allows differential measurement techniques to be implemented, where signals from multiple elements are combined to reject common-mode noise and induced voltages while maintaining accurate measurement of the target current.
Solution Approach 2:
The patent transitions from a single-point sensing approach to a distributed sensing array on the substrate plane. By arranging sensing elements at different positions and orientations, the system captures magnetic field information from multiple spatial dimensions, enabling more sophisticated noise rejection while measuring fast-varying currents.
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 sensor provides accurate current measurements with improved immunity to electromagnetic noise and reduced coupling, enabling precise detection of high-frequency currents without the need for bulky shields.
Implementation Method 1
a magnetic field sensor for sensing a current flowing in a first direction divided in at least two conductor portions separated in a second direction, the sensor comprising at least two sensing elements for sensing the magnetic field at two positions in a region between the two conductor portions
Implementation Method 2
external or stray magnetic fields can be compensated, without using large elements such as shields, or using shields with reduced dimensions
Data Source
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AI summary
A magnetic field sensor for sensing a current flowing in a first direction divided in at least two conductor portions separated in a second direction, the sensor comprising at least two sensing elements for sensing the magnetic field at two positions in a region between the two conductor portions, wherein the at least two sensing elements are adapted to sense the field at the respective position with the highest sensitivity in a direction being between 20 degrees and 160 degrees from a third direction being perpendicular to both the first and second direction, wherein the two positions are separated by a predetermined distance in the third direction