LIN Signalling Circuit With Delayed Pull-Down Against Dominant Lock
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Solution Overview
Problem
Existing signalling circuits in vehicle communication networks, such as LIN bus systems, are prone to malfunctions due to disturbances and noise, which can cause data loss and communication failures, especially when the slew rate control loop gets stuck in a dominant state, leading to unreliable data transmission.
Innovation Solution
The proposed signalling circuit incorporates a feedback circuit with a capacitive device and a pull-down device that introduces a predefined delay after a voltage transition, ensuring the communication network terminal returns to a recessive state even in noisy conditions, thereby maintaining data integrity by forcing a return to the recessive state after a predefined delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feedback circuit with capacitive device is added to control slew rate, then signal transmission reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback circuit that connects the output signal back to the input through a capacitive device. This feedback mechanism automatically controls the slew rate of the signal transitions without requiring external intervention, thereby improving signal transmission reliability by preventing dominant state locking while adding only minimal circuit complexity
Solution Approach 2:
The patent changes the electrical parameters of the signal by introducing a capacitive device in the feedback path. This capacitance modifies the slew rate characteristics of the signal transitions, enabling controlled signal propagation that prevents the circuit from getting stuck in dominant states, thus improving reliability with minimal added complexity
2Reliability
If pull-down device is added to force return to recessive state, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The patent incorporates a pull-down device that preemptively forces the signal line to return to the recessive state after a dominant state transition. This preliminary anti-action prevents the potential problem of dominant state locking before it can occur, thereby improving communication reliability while adding only a single device to the circuit
Solution Approach 2:
The pull-down device operates autonomously based on the signal transitions, automatically forcing the return to recessive state without requiring external control signals or complex timing circuits. This self-service mechanism improves reliability while minimizing the increase in device complexity
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 enhances the reliability and robustness of the signalling circuit by ensuring data frames are maintained even in noisy environments, preventing data loss and ensuring correct signal transmission by forcing the return to a recessive state after a predefined delay, thus improving communication reliability.
Implementation Method 1
A feedback circuit is connected between the first driver terminal and the driver control terminal and comprises a capacitive device
Implementation Method 2
a pull-down device that is arranged to connect the driver control terminal to ground after a predefined delay
Data Source
AI summary
A signalling circuit for a signal channel of a communication network comprises a communication network terminal connectable to the signal channel and to a voltage supply; an input terminal connectable to receive a transmit signal; a driver device comprising a first driver terminal connected to the communication network terminal, a second driver terminal connected to ground, and a driver control terminal connected to the input terminal; wherein the driver device is arranged to connect the communication network terminal to ground in response to a transition from a low to a high voltage driver control signal state of a driver control signal received at the driver control terminal. And the signalling circuit comprises a feedback circuit connected to the first driver terminal and the driver control terminal and comprising a capacitive device; and a pull-down device arranged to connect the driver control terminal to ground after a predefined delay after a transition of the transmit signal from a low to a high voltage transmit signal state.