Magnetic Sensor Compensation Loop for Induced EMF Inhibition
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Solution Overview
Problem
Conventional magnetic sensors using a magnetic converging plate are susceptible to induced electromotive forces caused by wires connected to Hall elements, leading to degraded response characteristics, especially in in-vehicle applications with non-uniform magnetic fields and disturbance fields.
Innovation Solution
The magnetic sensor incorporates compensation loops formed by wires crossing each other and a circuit, with parts of these loops covered by the magnetic converging plate, to cancel out induced electromotive forces and improve response characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall elements are arranged in the proximities of end parts of a magnetic converging plate to detect transverse magnetic fields, then detection capability for transverse magnetic fields is improved, but induced electromotive forces are generated in connecting wires which form closed loops relative to magnetic fields, degrading response characteristics
Solution Approach 1:
The patent applies the principle of converting harm into benefit by intentionally generating compensation electromotive forces in the opposite direction to cancel out the harmful induced electromotive forces. The wires are configured to form compensation loops that generate compensating electromotive forces when exposed to the same magnetic field changes, thereby converting the harmful induced electromotive forces into a beneficial cancellation effect that restores fast response characteristics.
2Ease of operation
If wires connecting Hall elements form closed loops relative to magnetic fields, then electrical connection is achieved, but induced electromotive forces are generated which degrade response characteristics
Solution Approach 1:
The patent maintains the necessary closed loop electrical connections while converting the harmful effect into a beneficial one by configuring the wire loops to generate compensating electromotive forces. The compensation loops are designed to experience the same magnetic field changes as the Hall element connections, generating opposite polarity electromotive forces that cancel out the induced interference, thus preserving both electrical connection functionality and fast response characteristics.
3Adaptability or versatility
If a magnetic sensor using a magnetic converging plate is used in in-vehicle applications with non-uniform magnetic fields, then versatility is improved, but output voltages due to vertical magnetic fields are not cancelled out completely, causing detection of disturbance magnetic fields
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the wire connections to form compensation loops that generate opposing electromotive forces before the actual measurement takes place. This preliminary configuration ensures that when disturbance magnetic fields or non-uniform vertical magnetic fields are present, the compensation loops are already positioned to generate counteracting electromotive forces, thereby canceling out the unwanted signals before they can affect the measurement accuracy.
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 solution effectively inhibits the influence of induced electromotive forces, enabling quicker responses and improved detection accuracy even in the presence of non-uniform or disturbance magnetic fields.
Implementation Method 1
a magnetic sensor that is formed by combining a thin film-like plate consisting of a ferromagnetic body such as a Ni—Fe alloy (referred to as a magnetic converging plate) and one pair of Hall elements and detects a magnetic field parallel with a substrate (referred to as a transverse magnetic field) supporting the plate and the one pair of Hall elements This magnetic sensor utilizes a function of converting the transverse magnetic field into magnetic fields perpendicular to the substrate (referred to as vertical magnetic fields) by attracting the lines of magnetic force of the transverse magnetic field with the magnetic converging plate
Implementation Method 2
one pair of Hall elements and detects a magnetic field parallel with a substrate
Implementation Method 3
induced electromotive forces are generated to the wires, and the response characteristics of the magnetic sensor are degraded compensation loops formed by wires crossing each other and a circuit, with parts of these loops covered by the magnetic converging plate, to cancel out induced electromotive forces
Data Source
AI summary
A magnetic sensor includes: a magnetic converging plate; Hall elements disposed on one surface side of the magnetic converging plate; wires connecting with the Hall elements; and a signal processing circuit that connects with these wires to receive a signal from the Hall element. Between the Hall element and the signal processing circuit, the two wires cross while being spaced apart from each other in a depth direction of a substrate, and forms a compensation loop between a cross of the two wires and the circuit, and in a planar view as seen in a depth direction, at least part of a region occupied by the compensation loop is covered by the magnetic converging plate. The compensation loop compensates an induced electromotive force caused to the closed loop formed by the wires including the Hall element.