Magnetic Sensor Compensation Coil Layout for Noise Reduction
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Solution Overview
Problem
The magnetic field generated from the end portion of the compensation coil in existing magnetic sensors interferes with the magnetosensitive element, causing noise and reducing detection accuracy.
Innovation Solution
The compensation coil is designed with one end and the other end extending along perpendicular surfaces of a molded member, with sections of the coil parallel to each other to cancel out magnetic fields, and the external magnetic body is structured to minimize interference with the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compensation coil is wound around the external magnetic body, then the magnetic field is directed in the axial direction, but a magnetic field is generated from the end portion of the compensation coil which becomes noise
Solution Approach 1:
The harmful magnetic field generation from the coil end is extracted and addressed separately by providing a specific structural arrangement for the coil end portion, distinguishing it from the main winding portion to prevent noise interference
Solution Approach 2:
A non-magnetic insulating structure acts as an intermediary between the coil end and the magnetosensitive element, preventing the magnetic field from the coil end from directly interfering with the sensor while allowing the functional magnetic field to pass through
2Ease of manufacture
If the end portion of the compensation coil is connected to the connecting pin, then connection is facilitated, but the position of the coil end changes causing magnetic field interference
Solution Approach 1:
The coil end position is predetermined and fixed in the design stage with respect to the connecting pin and external magnetic body, establishing a precise reference position before assembly to prevent positional variations
Solution Approach 2:
Instead of allowing the coil end to connect freely to the pin, the structure is inverted so that the coil end follows a predetermined path along the external magnetic body surface, with the pin serving as a fixed reference point rather than a flexible connection point
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 effectively reduces the influence of magnetic fields from the coil ends on the magnetosensitive element, enhancing detection accuracy and stability.
Implementation Method 1
an external magnetic body for collecting magnetic flux in a magnetosensitive element
Implementation Method 2
a compensation coil wound around the external magnetic body through the bobbin part of the molded member
Data Source
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AI summary
To reduce the influence that a magnetic field generated from the end portion of a compensation coil has on a magnetosensitive element. A magnetic sensor 1 includes an external magnetic body 30 for collecting a magnetic field to be detected in a sensor chip 20, a compensation coil 60 wound around the external magnetic body 30 through a bobbin part 51 of a molded member 50, and a connecting terminal 71 fixed to a terminal fixing part 52 of the molded member 50 and connected with one end of the compensation coil 60. The terminal fixing part 52 has a bobbin connecting surface S1 and a terminal fixing surface S2. The compensation coil 60 has, at its one end, a section 61 extending along the bobbin connecting surface S1 and a section 62 extending along the terminal fixing surface S2. With this configuration, it is possible to reduce the influence that a magnetic field generated from the end portion of the compensation coil has on a magnetosensitive element.