Magnetic Sensor Module Triangular Coil AC Calibration
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Solution Overview
Problem
Existing magnetic sensor modules face challenges in maintaining accuracy due to the need for continuous calibration of sensitivity during operation, which is difficult to achieve without interfering with external DC magnetic fields.
Innovation Solution
A magnetic sensor module comprising an IC chip with multiple coils generating AC calibration magnetic fields, allowing for sensitivity adjustment of multiple magnetic sensors without interfering with external DC fields, using a Wheatstone bridge circuit with magneto-resistive elements and a signal processing unit for precise sensitivity correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coil is used to generate calibration magnetic field, then sensitivity adjustment is enabled, but external DC magnetic fields are interfered with
Solution Approach 1:
The patent employs AC current instead of DC current to drive the coil, generating a periodic AC magnetic field for calibration. This periodic action enables sensitivity adjustment while avoiding interference with static DC magnetic fields, as the AC field can be distinguished and filtered from DC fields in the measurement system.
Solution Approach 2:
The patent changes the parameter of the calibration current from DC to AC, transforming the calibration magnetic field from a static field to a time-varying field. This parameter change allows the calibration process to occur without interfering with external DC magnetic fields, as the AC calibration field can be modulated and detected separately from DC fields.
2Productivity
If multiple magnetic sensors are calibrated simultaneously, then calibration efficiency is improved, but uniform application of calibration field becomes difficult
Solution Approach 1:
The patent uses a triangular-shaped coil instead of a conventional circular or rectangular coil. This asymmetric geometry creates a specific magnetic field distribution pattern that, when combined with the AC excitation, enables uniform calibration across multiple sensor elements positioned at different locations, solving the uniformity problem while maintaining high calibration efficiency.
Solution Approach 2:
The triangular coil design serves multiple functions simultaneously: it generates calibration fields for multiple magnetic sensors, provides uniform field distribution across the sensor array, and maintains AC excitation capability. This multi-functional design enables simultaneous calibration of multiple sensors with uniform field application.
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
Enables accurate and continuous sensitivity adjustment of magnetic sensors during operation, improving measurement accuracy and allowing for the use of smaller, cost-effective magnetic sensor chips by applying uniform calibration fields without interfering with external magnetic fields.
Implementation Method 1
applying AC current to a coil to generate a magnetic field
Implementation Method 2
magnetic sensor that detects magnetism in a direction of first axis
Data Source
AI summary
An object is to provide a magnetic sensor module that suppresses a size of a magnetic sensor chip while applying a uniform calibration magnetic field to a magneto-resistive element. Provided is a magnetic sensor module comprising an IC chip having a first coil; and a magnetic sensor chip that is disposed on a surface of the IC chip and includes a first magnetic sensor that detects magnetism in a direction of first axis, wherein a planar shape of the IC chip encompasses a planar shape of the magnetic sensor chip, and the first coil has a planar shape including three or more sides, and is, when seen in a cross section along at least one side of the planar shape, is formed so as to cover a region, in a direction of the one side, of the first magnetic sensor.