Magnetic Sensor Circuit with Temperature-Compensating Resistors
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Solution Overview
Problem
Existing magnetic sensor circuits face challenges in miniaturization due to the need for additional elements to compensate for changes in magnetoelectric conversion coefficients caused by stress or temperature changes, leading to increased size and reduced accuracy.
Innovation Solution
A magnetic sensor circuit configuration that includes resistors with specific temperature characteristics and switch circuits to compensate for changes in the Hall element's resistance, allowing for reduced offset voltages and miniaturization by using resistors with smaller temperature coefficient changes, thereby stabilizing the magnetoelectric conversion coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional elements (coils, resistive bodies) are added to compensate for stress changes in the Hall element, then the magnetoelectric conversion coefficient can be calibrated, but the device area increases and miniaturization becomes difficult
Solution Approach 1:
The patent combines the compensation function into the existing Hall element structure by forming compensation regions within the Hall element itself. The compensation regions are created by modifying the Hall element's structure (e.g., adding doped regions or geometric modifications) rather than adding separate external compensation components. This merging approach allows stress compensation to occur within the same device footprint, eliminating the need for additional mounting area while maintaining calibration accuracy.
2Reliability
If the Hall element resistance changes due to stress or long-term package changes, then the magnetoelectric conversion coefficient changes, but the signal processing accuracy degrades
Solution Approach 1:
The patent implements preliminary compensation by pre-configuring compensation regions within the Hall element structure that are designed to counteract anticipated stress effects. These compensation regions are formed during the manufacturing process with specific doping concentrations and geometric configurations that predictably compensate for stress-induced resistance changes. By preparing this compensation mechanism in advance, the system maintains accurate magnetoelectric conversion coefficients even when stress conditions change during operation or aging.
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 proposed configuration effectively compensates for temperature and stress-induced changes in the Hall element's resistance, enhancing the accuracy and miniaturization of the magnetic sensor circuit by using down-sizable elements like resistors, resulting in a compact and reliable magnetic sensor system.
Implementation Method 1
A magnetic sensor circuit using a magnetoelectric conversion element (Hall element, for example) has been used in various electronic devices as a non-contact type sensor.
Implementation Method 2
A magnetic sensor circuit configuration that includes resistors with specific temperature characteristics and switch circuits to compensate for changes in the Hall element's resistance
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
A magnetic sensor circuit includes a magnetoelectric conversion element having a plurality of terminals including at least a voltage supply terminal to which a drive voltage is applied, and a ground terminal, a switch circuit configured to output signals provided from any two of the terminals as a differential voltage, and a first resistor having a first temperature characteristic being a prescribed temperature characteristic. A current supplied from the voltage supply terminal flows to the ground terminal through the first resistor and the magnetoelectric conversion element.