Dual-Feedback Magnetic Detection Circuit for Strong Field Cancellation
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Solution Overview
Problem
Existing magnetic detection devices face challenges in increasing feedback current without reducing circuit resistance or increasing power supply voltage, leading to noise and size issues in the feedback magnetic field.
Innovation Solution
A magnetic detection device with a main operational amplifier and dual feedback circuits, where one feedback circuit generates a feedback voltage with inverted polarity, allowing for increased potential difference and feedback current without altering resistance or power supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the feedback current is increased to cancel a strong detection target magnetic field, then the feedback magnetic field strength is improved, but the noise in the feedback voltage increases when circuit resistance is reduced
Solution Approach 1:
The patent introduces a second feedback circuit that operates in parallel with the first feedback circuit, adding a new dimensional approach to feedback control. This dual-circuit configuration allows the system to increase feedback current capability without relying solely on reducing circuit resistance, thereby avoiding noise amplification while maintaining strong feedback magnetic field generation.
2Strength
If the feedback current is increased to cancel a strong detection target magnetic field, then the feedback magnetic field strength is improved, but the detection circuit size increases when power supply voltage is increased
Solution Approach 1:
The patent divides the feedback circuit into two separate circuits (first feedback circuit and second feedback circuit), each contributing to the overall feedback current. This segmentation allows the system to achieve high feedback current capability without requiring a single oversized circuit or excessively high power supply voltage, thereby controlling device size while maintaining strong feedback magnetic field generation.
3Device complexity
If a single feedback circuit is used, then the device complexity is low, but the feedback current magnitude is limited
Solution Approach 1:
The patent merges two feedback circuits (first feedback circuit and second feedback circuit) to work together in providing feedback current to the detection coil. This combination allows the system to achieve larger feedback current magnitude than a single circuit could provide, while keeping each individual circuit relatively simple in structure.
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 detection of magnetic fields by completely canceling the detection target field with a feedback magnetic field, ensuring linearity and improved detection accuracy without noise or size increase.
Implementation Method 1
The amorphous magnetic wire has a property of causing a magnetoimpedance effect (MI effect). That is, the amorphous magnetic wire has a property of causing a magnetization change corresponding to the strength of the magnetic field acting on the amorphous magnetic wire when an excitation current is supplied.
Implementation Method 2
The detection coil is wound around the amorphous magnetic wire, and outputs an induced voltage caused by a magnetization change of the amorphous magnetic wire.
Implementation Method 3
The feedback circuit is configured to connect an output terminal of the amplifier circuit and one end of the detection coil and magnetically apply negative feedback.
Data Source
AI summary
A magnetic detection device includes a magnetoimpedance sensor element, a main operational amplifier whose input terminals are connected to a first end and a second end of a detection coil, a first feedback circuit that is connected between an output terminal of the main operational amplifier and the first end of the detection coil and is configured to generate a first feedback voltage, and a second feedback circuit that is connected between the output terminal of the main operational amplifier and the second end of the detection coil and is configured to generate a second feedback voltage with a polarity that inverts a polarity of the first feedback voltage with respect to a predetermined reference voltage as a baseline.