Bus Transceiver Driver Simulation for Dominant-Recessive Damping

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Solution Overview

Problem

In bus systems, particularly in CAN and CAN FD communication, there is a tendency for oscillation during transitions from dominant to recessive bit states, leading to increased bit times and reduced transmission rates due to insufficient damping, which limits design flexibility and increases error rates.

Innovation Solution

The introduction of additional drivers on bus cores to reduce oscillation duration by actively managing the transition from dominant to recessive states, using driver simulations and RS timing control to minimize energy in the oscillating circuit and optimize bus state changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If additional drivers are added to reduce oscillation, then oscillation duration is reduced and transmission rate increases, but device complexity increases

Engineering Contradiction:
Improvetransmission rateVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The transceiver is divided into functional segments: a driver stage for signal transmission, a receiver stage for signal detection, and an oscillation reduction stage with additional drivers. Each segment handles specific tasks independently, allowing the oscillation reduction functionality to be added without redesigning the entire device, thus managing complexity while improving transmission rate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Additional driver circuits are introduced as intermediary elements between the transceiver and the bus wires. These intermediate drivers actively manage the transition between dominant and recessive states by providing controlled current paths, thereby reducing oscillation duration and enabling higher transmission rates without fundamentally changing the core transceiver architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If bit time is extended to dampen oscillation, then oscillation is reduced, but transmission rate decreases

Engineering Contradiction:
Improveoscillation dampingVSAvoidtransmission rate
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The additional drivers in the oscillation reduction stage are activated in advance during state transitions to preemptively dampen oscillations. By applying damping current before the oscillation can fully develop, the system achieves stable bus states without extending the bit time, thereby maintaining high transmission rates while ensuring signal stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The oscillation reduction stage dynamically changes electrical parameters (current magnitude and direction) during state transitions. By adjusting these parameters in real-time based on the transition state, the system effectively dampens oscillations without requiring longer bit times, thus preserving high transmission rates while achieving signal stability.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If additional drivers are added to manage state transitions, then oscillation is reduced and design freedom increases, but manufacturing complexity increases

Engineering Contradiction:
Improvedesign freedomVSAvoidease of manufacture
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The additional drivers in the oscillation reduction stage are designed with multi-functionality: they operate during dominant-to-recessive transitions to prevent oscillation, and can be configured for different bus topologies and termination schemes. This universal design allows the same circuit architecture to serve multiple application scenarios, increasing design freedom while maintaining manufacturing simplicity through standardized components.

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

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 approach reduces oscillation duration, allowing for higher bit rates, increased design freedom in bus topologies, and improved interference immunity by shifting emissions away from critical frequency ranges, thereby enhancing overall transmission speed and system performance.

Implementation Method 1

driving at least one suitable additional electrical current

Methodology Applied
Scientific EffectElectrical current: Conduction (electrical)

Implementation Method 2

reducing oscillation during transitions between different bit states

Methodology Applied
Scientific EffectOscillation damping: Damping

Data Source

PatentEP3665870B1Transceiver for a bus system for reducing an oscillation inclination upon transitioning between different bit state
Publication Date: 2021.07.21 ROBERT BOSCH GMBH
  • EP3665870B1 patent drawingFigure 1
  • EP3665870B1 patent drawingFigure 2
  • EP3665870B1 patent drawingFigure 3A~5B

AI summary

The invention relates to a transceiver (12; 120; 1200) for a bus system (1) and to a method for reducing an oscillation inclination upon transitioning between different bit states. The transceiver (12; 20; 1200) has a first driver (1211) for driving a signal for a first bus wire (41) of a bus (40) of the bus system (1), wherein an exclusive collision-free access of a participant station (10, 20, 30, 100) to the bus (40) of the bus system (1) is at least temporarily ensured in the bus system (1), a second driver (1212) for driving a signal for the second bus wire (42) of the bus (40), a first driver simulation (1213) for driving a signal for the first bus wire (41) in order to reduce currents supplied for the first bus wire (41) by the first driver (1211) and/or a second driver simulation (1214) for driving a signal for the second bus wire (42) in order to supply currents for the second bus wire (41) together with the second driver (1212), a receiver (122) for receiving a signal which is transmitted from a bus (40) of the bus system (1), and an oscillation reduction unit (15; 150) which is designed to actuate at least one of the driver simulations (1213, 1214) in order to drive a signal for the first and/or second bus wire (41, 42) if a state change of the received signal from a dominant bus state (402) to a recessive bus state (401) is detected.