Magnetic Field Sensor Self-Test via Alternating Current Driver
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Solution Overview
Problem
Magnetometers in portable and industrial systems require high energy efficiency and compact size, while also needing advanced self-monitoring capabilities for accurate magnetic field sensing, which existing technologies struggle to achieve effectively.
Innovation Solution
A magnetic field sensing device incorporating multiple magnetoresistor units, testing conductive lines, and a driver that alternates currents to enable a building-in self-test function, utilizing anisotropic magnetoresistors and Wheatstone bridges to sense magnetic fields and correct for errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If magnetoresistance sensors are used to achieve compact size and high energy efficiency, then device size and energy consumption are improved, but self-monitoring capability is insufficient
Solution Approach 1:
The patent implements self-service by enabling the magnetometer to perform self-tests using its own internal resources. The testing conductive lines and driver allow the device to autonomously generate test currents and monitor its own magnetoresistor units without requiring external testing equipment, thus maintaining reliability while keeping the device compact and energy-efficient.
Solution Approach 2:
The patent merges the sensing function and self-testing function into a single integrated device. The same magnetoresistor units serve both as sensing elements and as objects of self-test, while the testing conductive lines are integrated alongside the sensing structures. This consolidation eliminates the need for separate testing subsystems, resolving the contradiction between compact size and self-monitoring capability.
2Reliability
If multiple magnetoresistor units are added to enable self-testing, then self-monitoring capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the self-testing function into distinct components: testing conductive lines for current application and driver for control. This segmentation allows the self-testing capability to be added as a modular subsystem that works with the existing magnetoresistor array, rather than fundamentally redesigning the entire device architecture, thus limiting the increase in complexity.
Solution Approach 2:
The driver serves multiple functions: it drives the sensing operation and also performs self-testing by applying test currents. The magnetoresistor units serve dual purposes as both sensing elements and test subjects. This multi-functionality reduces the need for dedicated separate components, thereby limiting the increase in device complexity while maintaining self-monitoring capability.
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 device achieves high accuracy and energy efficiency in magnetic field sensing with a compact design, enabling self-testing and improved reliability for advanced applications.
Implementation Method 1
The first magnetoresistor units and the second magnetoresistor units include a plurality of anisotropic magnetoresistors
Implementation Method 2
The first magnetoresistor units and the second magnetoresistor units are electrically connected to form at least one Wheatstone bridge to output a voltage signal corresponding to a magnetic field component
Data Source
AI summary
A magnetic field sensing device includes first magnetoresistor units, second magnetoresistor units, a first testing conductive line, a second testing conductive line, and a driver. The first magnetoresistor units are arranged in a first direction. The second magnetoresistor units are arranged in the first direction, and the second magnetoresistor units are disposed on a side of the first magnetoresistor units in a second direction. The first testing conductive line is disposed on a side of the first magnetoresistor units in a third direction, and extends in the first direction. The second testing conductive line is disposed on a side of the second magnetoresistor units in the third direction, and extends in the first direction. The driver is configured to make two currents in a same direction and two currents in opposite directions pass through the first testing conductive line and the second testing conductive line at different times, respectively.