Modular Filter Device With Sliding Core For Flexible EMI Suppression

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Solution Overview

Problem

Existing filter devices for reducing electromagnetic interference, such as common-mode chokes and O-shaped cores, require complex and costly production processes, limiting flexibility and increasing costs, especially when integrating PI filters with separate capacitors, and restrict the customer's ability to opt-out or opt-in for filtering without redesigning the circuit.

Innovation Solution

A filter device with a core designed to slide onto a printed circuit board, allowing for easy and flexible installation of a PI filter with capacitors arranged to enclose the core, eliminating the need for additional wiring and enabling optional use without altering existing electronic components or circuit design, using a ferrite core for cost-effectiveness and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If common-mode chokes are introduced into the signal path by soldering or welding, then electromagnetic interference is reduced, but the circuit design cannot be optionally equipped with filters and production costs increase

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidoptional filter equipment
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The filter device is segmented into a separate modular unit consisting of the core and capacitors that can be independently assembled. The core is designed as a separate component with a passage that receives the circuit board, allowing the filter to be optionally equipped without redesigning the entire circuit. This segmentation enables customers to decide whether to equip the circuit with a filter based on their specific needs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circuit board is pre-designed with a receiving section that has conductor tracks running through it, prepared in advance to receive the core. The capacitors are pre-positioned on the circuit board at locations that will enclose the core when assembled. This preliminary preparation allows for easy optional assembly of the filter without requiring additional wiring or design changes.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If O-shaped cores are pushed over sheet metal lines with sequential processing, then filtering is achieved, but a large number of individual process steps and high production costs are required

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidproduction process complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The core and capacitors are merged into a single integrated filter device assembly. The core is designed with a passage that fits over the circuit board, and the capacitors are positioned to enclose the core, creating a complete Pi filter in one assembly unit. This merging eliminates the need for sequential individual process steps of soldering, welding, or clamping separate components, as the entire filter can be assembled in one operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The core is designed as a universal component with a passage dimensioned to accommodate the receiving section of the circuit board. The same core design can be used across different circuit board variants, and the filter device can be optionally assembled or omitted without requiring different core types. This universality simplifies manufacturing by using the same core component for all filter applications.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If capacitors are applied individually with separate welding, soldering, or clamping, then a Pi filter is formed, but production costs are additionally increased

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidproduction costs
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The capacitors are merged into the filter device assembly with the core, positioned at locations that will enclose the core when assembled. This creates a complete Pi filter as a single assembly unit, eliminating the need for separate welding, soldering, or clamping operations for each capacitor. The capacitors are pre-positioned on the circuit board during manufacturing, and the entire filter assembly can be installed in one step.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If the core passage is designed to accommodate the receiving section with electronic components, then the printed circuit board can be fully populated first and the core applied afterward, but the core must be precisely positioned to avoid damaging components

Engineering Contradiction:
Improveflexible installation timingVSAvoidcomponent protection during assembly
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The capacitors are positioned at specific locations on the circuit board that correspond to the end faces of the core. This local positioning ensures that when the core is assembled, the capacitors enclose the core and simultaneously protect it from slipping. The receiving section is designed with conductor tracks that guide the core into the correct position, ensuring precise positioning without damaging other electronic components.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The capacitors are pre-positioned on the circuit board at locations that will serve as protective elements during core assembly. These capacitors act as cushioning elements that prevent the core from slipping and damaging other electronic components. The receiving section is designed with conductor tracks that guide the core into the correct position, providing a protective path for assembly.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

Enables simple, cost-effective implementation of a PI filter that can be easily added or removed without altering the circuit board or electronic components, providing flexible electromagnetic interference filtering without increasing production complexity or costs.

Implementation Method 1

common-mode chokes, which consist of two oppositely wound coils with a soft-magnetic core, have been used to date to reduce electromagnetic interference

Methodology Applied
Scientific EffectElectromagnetic interference filtering: Magnetic Field

Implementation Method 2

These are usually introduced into the signal path to be filtered by soldering or welding

Methodology Applied
Scientific EffectCommon-mode choke filtering: Electromagnetic Induction

Implementation Method 3

using a ferrite core for cost-effectiveness and stability

Methodology Applied
Scientific EffectFerrite magnetic properties: Ferromagnetism

Data Source

PatentEP2868176B1Production-process-optimized filter device
Publication Date: 2020.09.02 CONTINENTAL AUTOMOTIVE GMBH
  • EP2868176B1 patent drawingFigure 1a~1b
  • EP2868176B1 patent drawingFigure 2
  • EP2868176B1 patent drawingFigure 3

AI summary

Filter device (1) for filtering electrical currents or electromagnetic interference, particularly Common-Mode interference, having a soft-magnetic core (20) with a passage (21), a printed circuit board (40) with a plurality of electronic components (41, 42) and a holding section (43), wherein the holding section (43) of the printed circuit board (40) can be put through the passage (21), characterized in that the passage (21) is designed such that the holding section (43) and the electronic components (41, 42) arranged on the holding section (43) can be put through the passage (21).