PCB-Integrated Inductor Core Structure for Lower Eddy Current Loss

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Solution Overview

Problem

Inductors in electronic circuits suffer from significant eddy current losses, leading to reduced efficiency and excessive heating, which is exacerbated by the miniaturization trend in electronic devices.

Innovation Solution

A circuit board integrated inductor design featuring a magnetic core embedded within the circuit board, with a coil partially or fully embedded and a grid-patterned first magnetic layer to reduce eddy current losses, and a second magnetic layer with alternating magnetic and insulating sub-layers to enhance inductance and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a traditional inductor is used in electronic circuits, then the inductor can limit current flow and form filter circuits, but the inductor suffers from large eddy current loss which greatly reduces efficiency and causes excessive heating

Engineering Contradiction:
Improveeddy current lossVSAvoidinductor efficiency
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The magnetic core is divided into multiple magnetic layers stacked in the thickness direction, with insulating layers between them. This segmentation breaks the continuous magnetic path into discrete segments, interrupting eddy current loops and significantly reducing eddy current losses while maintaining the inductor's filtering and current-limiting functions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inductor employs a composite structure combining magnetic layers (for high permeability and inductance) with insulating layers (for electrical isolation). This composite material approach allows the magnetic core to provide necessary magnetic properties while the insulating layers prevent eddy current formation at layer interfaces, resolving the contradiction between energy loss and efficiency

Inventive Principle:
Principle #40Composite materials

2Device complexity

If the inductor is integrated into the circuit board, then the device size can be reduced and manufacturing complexity lowered, but the eddy current loss increases due to miniaturization

Engineering Contradiction:
Improvemanufacturing complexityVSAvoideddy current loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The inductor is integrated directly into the circuit board by embedding the magnetic core and coil within the board structure. This merging of the inductor with the circuit board eliminates the need for separate inductor components and reduces assembly steps, while the multi-layer magnetic core structure simultaneously addresses eddy current loss concerns through internal insulation

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The magnetic core utilizes the thickness direction (z-axis) of the circuit board by stacking multiple magnetic layers vertically. This dimensional approach allows the inductor to achieve high inductance values within a compact footprint on the circuit board plane, reducing overall device size while the vertical stacking with insulating layers minimizes eddy current paths

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Loss of energy

If the magnetic core uses multiple stacked layers, then the inductance can be increased and eddy current loss reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveeddy current lossVSAvoidlayer alignment precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

Insulating layers are positioned between the magnetic layers to serve as intermediaries that provide both electrical isolation (reducing eddy currents) and mechanical support for alignment. These insulating layers act as spacers and positioning references during manufacturing, making it easier to maintain consistent layer spacing and alignment without requiring extremely high precision

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design effectively reduces eddy current losses, increases inductance, and allows for miniaturization of electronic devices by integrating the inductor within the circuit board, improving efficiency and reducing manufacturing complexity.

Implementation Method 1

an inductor, including a magnetic core and a coil, where the magnetic core is embedded in the circuit board, and the coil is at least partially embedded in the circuit board and surrounds an outer periphery of the magnetic core

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The inductor in the art may have a large eddy current loss, such that an efficiency of the inductor may be greatly reduced, causing excessive heating

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentEP4675652A1Circuit board integrated inductor, inductor, and electronic device
Publication Date: 2026.01.07 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP4675652A1 patent drawingFigure 1~2
  • EP4675652A1 patent drawingFigure 3~4
  • EP4675652A1 patent drawingFigure 5~7

AI summary

A circuit board integrated inductor includes: a circuit board; and an inductor, including a magnetic core and a coil. The magnetic core is embedded in the circuit board, and the coil is at least partially embedded in the circuit board and surrounds an outer periphery of the magnetic core. The magnetic core includes a first magnetic layer and a second magnetic layer insulated from the first magnetic layer; the first magnetic layer includes a plurality of magnetic sub-members, each of the plurality of magnetic sub-members extends along a first direction, and the plurality of magnetic sub-members are spaced apart from each other along a second direction and arranged on a surface of the second magnetic layer, wherein the first direction intersects the second direction.