Magnetic Balance Current Sensor with Multi-Config Feedback Coils
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Solution Overview
Problem
Magnetic balance type current sensors face challenges in miniaturization and efficiently handling various measurement ranges due to the necessity of switch circuits and complex coil configurations, which complicates the integration of feedback coils and increases the number of mask patterns required for wafer formation.
Innovation Solution
The design includes multiple feedback coils with varying coil configurations, such as different distances from a reference plane and spiral-shaped windings, allowing for adjustable canceling magnetic fields by changing connections between electrode sections and wiring lines, thereby reducing the footprint and enabling efficient handling of various measurement ranges without increasing the number of mask patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switch circuits are used to switch between different feedback coils for various measurement ranges, then the sensor can handle diverse measurement requirements, but the device complexity increases and miniaturization becomes difficult
Solution Approach 1:
The feedback coil is divided into multiple independent coil sections (first coil section, second coil section, third coil section) that can be independently connected to form different feedback coil configurations. This segmentation allows the sensor to handle various measurement ranges by selectively connecting different sections, eliminating the need for complex switch circuits while maintaining adaptability.
Solution Approach 2:
The multiple coil sections are designed to serve multiple functions by being connectable in different configurations (series, parallel, or individually). The same physical coil sections can provide different feedback magnetic field strengths depending on how they are connected, making the structure universal and eliminating the need for separate circuits for different measurement ranges.
2Reliability
If electrode sections are enlarged to avoid short circuits with coil wire sections, then wire bonding reliability improves, but the coil area increases and miniaturization is impeded
Solution Approach 1:
The electrode sections are positioned outside the coil wire sections in the planar layout, separating their spatial locations. This dimensional arrangement prevents short circuits between bonding wires and coil wires without requiring enlarged electrode areas, thus maintaining both reliability and compactness.
Solution Approach 2:
The electrode sections are extracted from the coil wire section area and placed in separate locations. This separation allows independent optimization of each component - the coil wire sections maintain their compact spiral design while the electrode sections are positioned where they can be reliably bonded without risk of short circuits.
3Adaptability or versatility
If multiple mask patterns are used for wafer formation to create complex coil configurations, then various feedback coil structures can be achieved, but manufacturing complexity increases
Solution Approach 1:
The same basic coil pattern structure is designed to serve multiple functions by varying the connection configurations of the coil sections. Different feedback coil structures (series, parallel, individual connections) are achieved by changing electrical connections rather than creating different physical patterns, reducing the number of mask patterns needed for wafer fabrication.
Solution Approach 2:
The coil configuration is made dynamically adjustable through electrical connections rather than fixed physical patterns. The same physical coil sections can be electrically reconfigured to provide different feedback characteristics, allowing versatile coil configurations to be achieved without complex multi-pattern wafer fabrication.
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 configuration allows for a compact, high-sensitivity current sensor that can respond to diverse measurement requirements, achieving miniaturization and maintaining detection accuracy across different ranges without the need for complex switch circuits.
Implementation Method 1
the characteristics of the magnetic detection element change depending on a magnetic field induced by a current to be measured. The plurality of coils are connected in series and disposed in the vicinity of the magnetic detection element. A feedback current flows through the plurality of coils, and thus the plurality of coils generate a canceling magnetic field that cancels out the induced magnetic field.
Implementation Method 2
a magnetic detection element, a plurality of coils, and a switch circuit. The characteristics of the magnetic detection element change depending on a magnetic field induced by a current to be measured.
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
[Object] There is provided a magnetic balance type current sensor that includes a magnetic detection element and a plurality of coils. The characteristics of the magnetic detection element change depending on an induced magnetic field induced by a current to be measured, and each of the plurality of coils includes a coil wire section disposed on a surface located away from a reference plane containing a sensitivity axis direction of the magnetic detection element. Each of the plurality of coils includes a lead wire section whose one end portion is connected to one end portion of the coil wire section, and each of the plurality of coils includes two electrode sections that are individually located at each end of each of the plurality of coils and that are electrically connected individually to the coil wire section and to the lead wire section. Each of the plurality of coils is capable of generating a canceling magnetic field when a feedback current is passed by using the two electrode sections as an applying section. The lead wire sections and the coil wire sections have crossing portions in each of which one of the lead wire sections and one of the coil wire sections are layered with an insulating section interposed so as to overlap each other in a first direction, which is a winding axis direction of the coil wire sections. The two electrode sections are located outside envelope curves of the coil wire sections when viewed in the first direction. The magnetic balance type current sensor is capable of efficiently responding to various requirements concerning measurement ranges and the like.