Ferromagnetic Shielding in PCB Layers for Magnetic Interference

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Solution Overview

Problem

Circuitry routing in printed circuit boards (PCBs) underneath inductors and other electromagnetic interference (EMI) emitting components is challenging due to magnetic fields inducing noise into signals, leading to wider PCB area requirements and potential for noisy signals during operation.

Innovation Solution

Laminating ferromagnetic material, such as ferrite, into the PCB structure to create magnetic shielding, allowing signal traces to be routed directly underneath power delivery circuitry and high current carrying components, reducing magnetic interference and freeing up space on the PCB.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ferromagnetic material is laminated into PCB layers to create magnetic shielding, then magnetic interference is reduced and signal quality is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvesignal qualityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining ferromagnetic material (ferrite) with standard PCB substrate materials to create a multi-layer structure that provides both magnetic shielding and electrical insulation. The ferromagnetic layer is laminated between non-magnetic substrate layers, creating a composite structure that leverages the magnetic properties of ferrite while maintaining the electrical and mechanical properties of the PCB substrate, thereby reducing magnetic interference without completely redesigning the manufacturing process

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The ferromagnetic material acts as an intermediary element between the magnetic source (inductor) and the signal traces. By placing the ferrite layer in the intermediate layers of the PCB stack, it mediates the magnetic field interaction, absorbing and redirecting magnetic flux to protect sensitive signals from EMI while allowing the signal traces to be routed underneath the inductor without direct magnetic exposure

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If signal traces are routed underneath inductors and EMI emitting components, then PCB area is reduced, but magnetic fields induce noise into signals

Engineering Contradiction:

ImprovePCB areaVSAvoidmagnetic interference

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful magnetic field generated by the inductor into a beneficial shielding effect by introducing ferromagnetic material. The ferrite layer absorbs and redirects the magnetic flux that would otherwise interfere with signal traces, transforming the EMI problem into a protective magnetic shield that actually protects the circuitry while allowing compact routing underneath the inductor

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If ferromagnetic material is applied to intermediate layers, then magnetic shielding is created, but PCB layer structure becomes more complex

Engineering Contradiction:

Improvemagnetic field shieldingVSAvoidPCB layer structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by placing ferromagnetic material specifically in the intermediate layers where magnetic shielding is most needed, rather than throughout the entire PCB structure. The ferrite is strategically positioned between the inductor and the signal traces in the middle layers, providing targeted magnetic shielding exactly where the magnetic interference problem occurs, while leaving other PCB layers unchanged and maintaining standard manufacturing processes

Inventive Principle:

Principle #3Local quality

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 approach reduces PCB size, increases battery capacity and size within the same chassis space, and decreases design and production costs by minimizing the need for wider PCB areas and reducing the risk of noisy signals.

Implementation Method 1

ferromagnetic material applied to a first of the one or more intermediate layers... to provide a shield for signal routing traces... from a magnetic field produced by the magnetic source

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

Laminating ferromagnetic material, such as ferrite, into the PCB structure to create magnetic shielding

Methodology Applied

Scientific EffectMagnetic shielding: Magnetic Field

Data Source

PatentEP3993568A1Ferromagnetic material to shield magnetic fields in substrate

Publication Date: 2022.05.04 INTEL CORP

Figure 1A~1B
Figure 1C~1D
Figure 1E~1F

AI summary

Embodiments of the present disclosure are directed to a substrate with a plurality of layers including a top layer (102a,102b), one or more intermediate layers (106) and a bottom layer (108). Ferromagnetic material (104) applied to a first of the one or more intermediate layers (104) in an area underneath a magnetic source (100) disposed on an outer surface of the top layer (102a,102b), where the ferromagnetic material (104) is to provide a shield for signal routing traces in one or more other intermediate layers (106) or the bottom layer (108) underneath the first intermediate layer (106), from a magnetic field produced by the magnetic source (100). Other embodiments may be described and/or claimed.