Capacitive Cable Detection Without Extra Pins

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Solution Overview

Problem

Existing cable detection systems require additional conductors and pins, which can be undesirable or impossible in certain situations, and rely on mechanical switches that are cumbersome, expensive, and unreliable, making it difficult to detect the presence and type of cables, especially in existing connector forms.

Innovation Solution

A cable detection system using a source of input electrical AC signal coupled to a first lead pin and a detector on a second lead pin, utilizing capacitive coupling to determine the connection and type of cable based on amplitude-dependent characteristics of the detected AC output signal, without the need for additional pins or mechanical switches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If additional conductors and pins are included in the cable connector for cable detection, then cable presence and type detection capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvecable presence and type detection capabilityVSAvoidconnector structure complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent makes existing cable conductors serve dual purposes: both signal transmission and cable detection. By applying an AC test signal to existing conductors and measuring the resulting AC voltage through capacitive coupling, the system eliminates the need for dedicated detection conductors or pins, thereby reducing connector complexity while maintaining detection capability

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

Solution Approach 2:

The cable itself provides the detection mechanism through its inherent capacitive coupling between conductors. The cable's physical presence and type are detected by measuring the AC voltage generated through its own capacitive properties, without requiring external detection components within the cable

Inventive Principle:
Principle #25Self-service

2Difficulty of detecting and measuring

If mechanical switches or sensors are used for cable detection, then cable presence detection is achieved, but device complexity, cost, and reliability issues arise

Engineering Contradiction:
Improvecable presence detection capabilityVSAvoiddetection system reliability
Core Design Contradiction:
Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent replaces mechanical switches and sensors with an electrical field-based detection method. By using capacitive coupling to detect cable presence through AC voltage measurement, the system eliminates moving parts and mechanical contact, thereby improving reliability while reducing complexity and cost

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a separate coding resistor is included within the cable for cable type identification, then cable type detection precision is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvecable type detection precisionVSAvoidcable manufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent detects cable type by measuring differences in capacitive coupling characteristics rather than using physical coding components. By analyzing the AC voltage response generated through capacitive coupling, the system identifies cable types based on their inherent electrical properties, eliminating the need for coding resistors and simplifying manufacturing

Inventive Principle:
Principle #35Parameter changes

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 reliable detection of cable presence and type without additional pins or mechanical switches, allowing for efficient integration into existing connector forms and reducing costs, while preventing interference with other signals by automatically turning off the AC signal after detection.

Implementation Method 1

The detector detects an electrical AC output signal derived by capacitive coupling of the input electrical AC signal occurring within a cable incorporating first and second leads corresponding to the first and second lead pins

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP2092357B1A cable detection system
Publication Date: 2019.02.20 DRAEGER MEDICAL SYSTEMS INC
  • EP2092357B1 patent drawingFigure 1a~1c
  • EP2092357B1 patent drawingFigure 2~3
  • EP2092357B1 patent drawingFigure 4

AI summary

A cable detection system, includes a source (16) of an input electrical AC signal for coupling to a first lead pin of a cable connector. A detector (42) is coupled to a different second lead pin of the cable connector (12). The detector detects an electrical AC output signal derived by capacitive coupling of the input electrical AC signal occurring within a cable incorporating first and second leads corresponding to the first and second lead pins. The detector further enables a determination of whether the cable is connected to the cable connector in response to an amplitude dependent characteristic of the detected AC output signal.