Magnetic Sensor Grade-Separation Junction for Induced EMF Cancellation
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Solution Overview
Problem
Conventional current sensors, particularly those using Hall-effect sensors, face challenges in suppressing induced electromotive forces generated by drastic changes in magnetic flux density, leading to response delays and increased size due to the need for larger interconnection loops to cancel these forces, which is difficult to achieve with wire interconnections.
Innovation Solution
The magnetic sensor design incorporates a grade-separation junction on the IC with metal interconnections that cross each other at different heights, forming loops that generate induced electromotive forces of the same and opposite polarities to the output voltage, allowing for precise control and cancellation of these forces, thereby reducing the size and improving response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the area of interconnection loop is increased to cancel induced electromotive force, then the induced electromotive force is suppressed, but the size of current sensor increases
Solution Approach 1:
The patent utilizes three-dimensional space by forming interconnection loops that extend in multiple layers above and below the substrate surface. The first and second interconnection loops are positioned at different heights (different z-dimensions), allowing cancellation of induced electromotive forces without requiring larger planar area on the substrate. This vertical arrangement enables effective loop areas for cancellation while maintaining compact sensor footprint.
Solution Approach 2:
The patent embeds multiple interconnection loops within the three-dimensional structure of the substrate and packaging. The first and second interconnection loops are nested in different spatial layers, with wire interconnections passing through or around these loops. This nesting allows the loops to occupy overlapping or adjacent three-dimensional spaces, achieving cancellation functionality without increasing the external dimensions of the sensor.
2Device complexity
If wire interconnections are used to connect Hall-effect sensor and IC, then the number of components is reduced, but induced electromotive force cannot be sufficiently suppressed
Solution Approach 1:
The patent introduces substrate traces as intermediary elements between the wire interconnections and the IC mounting area. These substrate traces form controlled interconnection loops that actively cancel induced electromotive forces. The substrate acts as an intermediary structure that provides both electrical connection pathways and cancellation loop geometry, eliminating the need for separate cancellation components while maintaining low component count.
Solution Approach 2:
The substrate serves multiple functions simultaneously: it provides mechanical support, electrical connections through trace patterns, and active cancellation of induced electromotive forces through strategically designed interconnection loops. The wire interconnections also serve dual purposes by forming part of the cancellation loop geometry while maintaining electrical connectivity. This multi-functionality achieves suppression without adding dedicated cancellation components.
3Object-affected harmful factors
If larger interconnection loops are formed on substrate to cancel induced electromotive force, then cancellation effect is improved, but manufacturing precision becomes difficult to achieve
Solution Approach 1:
By transitioning from two-dimensional planar loops to three-dimensional loops extending above and below the substrate, the patent achieves effective cancellation loop areas without requiring proportionally larger planar dimensions. The vertical dimension provides additional space for loop formation, allowing cancellation loops to be formed within compact footprints while maintaining manufacturability through standard PCB trace routing practices.
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 suppresses the influence of induced electromotive forces, enabling quick-response performance required for current sensors by accurately controlling the areas of interconnection loops and stabilizing output voltage within microseconds.
Implementation Method 1
a Hall-effect sensor that is a magnetic sensor varies its output voltage in proportional to a magnetic flux density
Implementation Method 2
an induced electromotive force of a measurable magnitude is superimposed on the output voltage
Data Source
AI summary
A magnetic sensor of the present invention includes a Hall-effect sensor configured to detect magnetism and an IC being configured to drive the Hall-effect sensor and perform signal processing therefor and having two or more metal interconnection layers. The Hall-effect sensor and the IC are electrically connected to each other via wire interconnections and sealed in one package. Metal interconnections on the IC to input output voltage of the Hall-effect sensor to a signal processing unit of the IC have a grade-separation junction portion in order to suppress an induced electromotive force which a change in the magnetic flux density externally applied generates at output terminals of the Hall-effect sensor, the wire interconnections connected to output electrode pads of the Hall-effect sensor, and the metal interconnections to input the output voltage of the Hall-effect sensor to the signal processing unit of the IC.