CAN XL Receiver Mode Switching for False Differential Signal Detection
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Solution Overview
Problem
Existing CAN XL transceivers in serial bus systems incorrectly detect low unwanted voltage difference levels due to non-idealities in the bus system, leading to increased error rates and reduced transmittable bit rates.
Innovation Solution
A transmitting/receiving device with a receiver module and operating mode control module that switches between two operating modes based on differential signal evaluation, allowing it to detect and adjust to the current communication phase, reducing errors and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-bandwidth comparator is used to detect the communication phase FAST in CAN XL, then the detection capability is improved, but false detection of low unwanted voltage difference levels occurs due to non-idealities in the bus system
Solution Approach 1:
The patent introduces an intermediary evaluation mechanism that processes the comparator output before final detection. The evaluation unit analyzes the comparator signal to distinguish between genuine communication phase indicators and false signals caused by bus non-idealities, thereby maintaining high detection precision while eliminating false detections that would compromise reliability
Solution Approach 2:
The system implements feedback by continuously monitoring the comparator output and using evaluation logic to determine whether detected voltage differences represent actual communication phase changes or artifacts from bus reflections and interference. This feedback mechanism allows the system to adapt its detection behavior based on the actual bus conditions, resolving the contradiction between sensitivity and reliability
2Productivity
If the receiver module operates in the second operating mode for CAN XL data phase, then the transmission rate is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the operating mode selection variable rather than fixed. The receiver module dynamically switches between the first operating mode (lower power, suitable for arbitration phase) and the second operating mode (higher performance, suitable for data phase) based on the current communication phase detection, thereby optimizing the balance between transmission rate and power consumption according to actual operational requirements
Solution Approach 2:
The system changes operational parameters by adjusting the receiver module's operating mode based on detected communication phase. The evaluation unit determines when to switch parameters (operating modes) based on voltage difference evaluation, allowing the system to achieve high transmission rates only when necessary while reducing power consumption during phases where lower performance is acceptable
Data Source
AI summary
A transmitting/receiving device for a subscriber station of a serial bus system. The transmitting/receiving device has a receiver module for serially receiving differential signals from a bus and for generating a digital reception signal for a communication control device, an operating mode control module for switching the receiver module between a first operating mode and a second operating mode so that the receiver module is configured to generate the digital reception signal in the first operating mode based on differential signals generated using a first physical layer and in the second operating mode based on differential signals generated using a second physical layer, and a first evaluation block for evaluating whether a predetermined number of falling edges and/or rising edges occurs serially in the digital reception signal and whether the reception signal that comprises the edges that occurred is based on differential signals generated using the second physical layer.