Filter Circuit Ground Path Using Cable Wire

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Solution Overview

Problem

Filter circuit mounting units on printed circuit boards face challenges in effectively reducing noise propagation from the ground path to the power supply line due to adjacent wiring, which either fails to achieve sufficient noise reduction or requires increased board size by spacing the power supply line and ground path apart.

Innovation Solution

The use of cable wires as ground paths for filter circuits, spaced apart from the printed circuit board, allows for effective noise reduction without increasing the board size, with multiple stages of filter circuits and varying noise levels addressed by different ground path configurations, including cable wires and board-patterned wiring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the power supply line and ground path are spaced apart to prevent noise propagation, then noise reduction effect is improved, but the size of the printed circuit board increases

Engineering Contradiction:
Improvenoise propagationVSAvoidprinted circuit board size
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The ground path is moved from the two-dimensional plane of the printed circuit board to the third dimension by using a cable wire that extends vertically from the board surface. This dimensional transition allows the ground path to be spatially separated from the power supply line without increasing the board's footprint area.

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

Solution Approach 2:

A cable wire serves as an intermediary element connecting the filter circuit to the ground terminal. This cable wire acts as a mediator that carries the ground path outside the board plane, enabling noise suppression while maintaining compact board dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If the power supply line and ground path are placed adjacent to each other for compact layout, then board size is reduced, but radiation noise propagates from the ground path to the power supply line

Engineering Contradiction:
Improveprinted circuit board sizeVSAvoidradiation noise
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

By transitioning the ground path to three-dimensional space using a cable wire, the invention achieves spatial separation from the power supply line in the vertical dimension, thereby preventing radiation noise coupling while maintaining compact two-dimensional board layout.

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

3Ease of manufacture

If ground paths are formed by patterning on the printed circuit board, then manufacturing is simplified, but noise reduction effectiveness is insufficient due to adjacent wiring constraints

Engineering Contradiction:
Improveground path fabricationVSAvoidnoise propagation
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The cable wire serves as an intermediary that bridges the filter circuit and ground terminal outside the board plane. This approach maintains the simplicity of board-level patterning for other connections while introducing a specialized intermediate element to achieve the noise reduction function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The ground path transitions from being confined to the two-dimensional board plane to extending into the third dimension via cable wire, enabling effective noise separation while preserving the simplicity of standard PCB manufacturing processes for other circuit elements.

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

Data Source

PatentEP2278694B1Filter circuit mounting unit and power source unit
Publication Date: 2017.06.28 DAIKIN INDUSTRIES LTD
  • EP2278694B1 patent drawingFigure 1
  • EP2278694B1 patent drawingFigure 2
  • EP2278694B1 patent drawingFigure 3

AI summary

Filter circuit(s) (60, 70) and switching circuit(s) (20, 40) are mounted on a printed circuit board (51). A ground path of the filter circuit (70) is composed of a ground wire (78) arranged so as to be spaced apart from the printed circuit board (51).