Data Connection Protection Circuit for Overvoltage Without Bandwidth Loss

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Solution Overview

Problem

Existing protective circuits for electronic devices in data communication face challenges such as high manufacturing costs and reduced transmission bandwidth due to the complexity of galvanic isolation and the limitations of series resistors, which fail to effectively protect against overvoltages and leakage currents.

Innovation Solution

A protective circuit with a parallel configuration of a diode and capacitor, where resistors are connected to maintain DC voltage references, preventing charging and discharging due to leakage currents and providing a high-resistance barrier against overvoltages, while allowing transmission of alternating components and DC voltage components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If galvanic isolation is implemented using magnetic and/or optical isolators, then protection against overvoltages is improved, but device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improveprotection against overvoltagesVSAvoidcomplexity of isolators
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential protective function from complex galvanic isolation systems. Instead of implementing full magnetic or optical isolators, the invention uses a simplified circuit with a series resistor and parallel clamp diodes that perform the critical protection function without the complexity of traditional isolators.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, complex isolators with inexpensive semiconductor components (resistors and diodes) that can be easily integrated into the circuit. These components provide adequate protection for the intended application without the high cost and complexity of magnetic or optical isolators.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If series resistors are connected to limit current, then protection against overvoltages is improved, but transmission bandwidth is reduced due to low-pass effect

Engineering Contradiction:
Improveprotection against overvoltagesVSAvoidtransmission bandwidth
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent merges the protection function with the signal transmission path by placing the series resistor directly in the data communication line. This allows the same circuit element to serve dual purposes: limiting harmful currents while still permitting data signals to pass through to the parallel clamp diodes for protection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The parallel clamp diodes act as intermediaries that protect the receiving circuitry from overvoltages caused by series resistance. When voltage exceeds the diode breakdown voltage, the diodes conduct and clamp the voltage, preventing damage while allowing the series resistor to remain in place for current limiting.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If series resistors are used to prevent current flow, then protection against leakage currents is improved, but transmission bandwidth is limited

Engineering Contradiction:
Improveprotection against leakage currentsVSAvoidtransmission bandwidth
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies protection with local quality by using parallel clamp diodes positioned specifically at vulnerable points in the circuit. This targeted approach provides protection exactly where needed without requiring series resistors that would broadly limit bandwidth across the entire communication channel.

Inventive Principle:
Principle #3Local quality

4Reliability

If complex isolators are implemented, then protection reliability is improved, but manufacturing cost increases

Engineering Contradiction:
Improveprotection reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive magnetic and optical isolators with inexpensive semiconductor components (resistors and diodes) that can be easily manufactured and integrated. This standard component approach significantly reduces manufacturing cost while providing adequate protection for the application.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 solution enables reliable protection of electronic device connections without restricting bandwidth, allowing for scalable protection and effective transmission of static signal levels, effectively preventing damage from overvoltages and leakage currents.

Implementation Method 1

a capacitor circuit (114) comprising at least one capacitor (C1)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a diode (112) and a capacitor circuit (114) comprising at least one capacitor (C1), wherein the anode (112a) of the diode (112) is connected to the first terminal (110a) of the parallel circuit (110)

Methodology Applied
Scientific EffectDiode rectification: Diode

Implementation Method 3

A first resistor (116a) is connected between the second terminal (110b) of the parallel circuit and a first electrical reference potential

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3672009B1Protection circuit, electronic device and method for operating an electronic device
Publication Date: 2023.10.04 MARELLI GERMANY GMBH
  • EP3672009B1 patent drawingFigure 1~3
  • EP3672009B1 patent drawingFigure 4~5
  • EP3672009B1 patent drawingFigure 6~7

AI summary

Protection circuit for a connection of an electronic device, in particular a control unit, which can be used for data communication with another unit, wherein the protection circuit comprises a parallel circuit consisting of a diode and a capacitor circuit comprising at least one capacitor, wherein a first connection of the parallel circuit can be connected to the connection of the electronic device, and wherein a second connection of the parallel circuit can be connected to the other unit, and wherein an anode of the diode is connected to the first connection of the parallel circuit.