Bus Transceiver Resistance Damping for CAN Oscillation Control

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Solution Overview

Problem

Existing bus systems suffer from unwanted oscillations that are difficult to suppress without complex masking units, which are inefficient and cumbersome to implement.

Innovation Solution

A transmit/receive device for bus systems that uses a predefinable electrical resistance to connect bus terminals for a predefined initial period, allowing flexible damping of oscillations by activating the resistance for an optimal duration based on specific operating parameters, such as rising edges or state transitions, using a receiving comparator with multiple thresholds to determine the duration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a masking element is used to suppress bus oscillations, then oscillation suppression is achieved, but device complexity increases

Engineering Contradiction:
Improvebus oscillationsVSAvoidmasking element complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the oscillation suppression function from a complex masking element and implements it using a simple predefinable electrical resistance connected between bus terminals. This resistance is activated only during specific initial periods when oscillations occur, providing the same damping effect with significantly reduced device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a temporary, simple electrical resistance that is activated only for a predetermined initial period when oscillations are detected. This disposable-like approach replaces the complex masking element, providing adequate oscillation suppression during the critical initial phase without requiring continuous complex protection.

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

2Object-affected harmful factors

If electrical resistance is connected for a longer duration, then oscillation damping is improved, but energy consumption increases

Engineering Contradiction:
Improvebus oscillationsVSAvoidenergy consumption
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by connecting the electrical resistance for a predetermined initial period before normal operation resumes. This preliminary damping action is sufficient to suppress oscillations that occur during transitions, and the resistance is then deactivated, avoiding unnecessary energy consumption during steady-state operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The resistance is activated periodically or transiently only when oscillations are detected during specific initial periods, rather than continuously. This periodic activation pattern provides effective oscillation suppression while minimizing energy consumption during normal operational phases.

Inventive Principle:
Principle #19Periodic action

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

Effectively reduces unwanted bus oscillations by damping them efficiently and precisely without the need for complex masking units, ensuring optimal operation and reduced interference.

Implementation Method 1

connecting the first and second bus terminals via a predefinable electrical resistance for a predefinable first period of time

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

greater damping results from the added resistance during this initial period

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP3766216B1Transmission/reception device for a bus system, and method of operation therefor
Publication Date: 2026.01.28 ROBERT BOSCH GMBH
  • EP3766216B1 patent drawingFigure 1~2
  • EP3766216B1 patent drawingFigure 3~4
  • EP3766216B1 patent drawingFigure 5

AI summary

The invention relates to a transmission/reception device (10; 10a) for a bus system (1; 2), wherein the transmission/reception device (10; 10a) has a first bus connection (12a) for connection to a first signal line (1a; CAN_H) of the bus system (1; 2), a second bus connection (12b) for connection to a second signal line (1b; CAN_L) of the bus system (1; 2) and a reception unit (18) for receiving a bus received signal (BE) from the first and second bus connections (12a, 12b), wherein the transmission/reception device (10; 10a) is designed to connect (210) the first and second bus connections (12a, 12b) to one another via a prescribable electrical resistance (R) for a prescribable first period of time, wherein the prescribable first period of time is selectable on the basis of at least one operating variable of the reception unit (18).