Differential Bus Failure Detection Using Dynamic Voltage Ranges
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Solution Overview
Problem
Detecting failures in high-speed networks is complex due to variability in network parameters, ground shift, common mode choke effects, and external disturbances, making it difficult to accurately determine voltage ranges and identify failure conditions in differential bus systems like FlexRay and CAN.
Innovation Solution
A method and device for detecting failures on differential buses by determining allowed voltage ranges based on minimum and maximum loads, comparing differential bus voltages with these ranges, and determining failure states, which involves measuring currents, comparing voltages during signal transmission, and using a reference generator to define allowed voltage ranges, allowing for the detection of broken wires, short circuits, and wire connections to ground or supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional failure detection methods are used in high-speed networks, then the detection process is simple, but the accuracy is poor due to network parameter variability, ground shift, common mode choke effects, and external disturbances
Solution Approach 1:
The patent introduces an intermediary detection mechanism that measures the actual current flowing through the transmitter's output stage and uses this information to dynamically calculate the expected voltage range. This intermediary current measurement serves as a mediator between the transmitter and the voltage monitoring function, enabling accurate failure detection despite network parameter variability, ground shifts, and common mode choke effects by referenceing the voltage expectation to the actual current state rather than fixed specifications.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual current in the transmitter's output stage and using this feedback information to dynamically adjust the expected voltage range calculations. The system compares the actual measured voltage against the dynamically calculated expected range based on the feedback current measurement, enabling adaptive failure detection that accounts for changing network conditions, ground shifts, and disturbances.
2Measurement precision
If fixed voltage ranges are used for failure detection, then the detection method is simple, but it cannot accurately identify failure conditions due to variability in network parameters and ground shift
Solution Approach 1:
The patent applies dynamics by transitioning from fixed voltage ranges to dynamically calculated voltage ranges that adapt to changing network conditions. The expected voltage range is continuously updated based on the actual current measurement in the transmitter's output stage, allowing the detection system to adapt to network parameter variability, ground shifts, and common mode choke effects in real-time.
Solution Approach 2:
The patent changes the parameter used for voltage range determination from fixed specification values to dynamically calculated values based on actual operating conditions. By using the measured current in the output stage as a basis for calculating the expected voltage range, the system adapts the voltage parameter to reflect actual network conditions, improving both accuracy and adaptability.
3Reliability
If comprehensive failure detection is implemented, then the reliability is improved, but the device complexity increases due to additional measurement and comparison mechanisms
Solution Approach 1:
The patent merges the current measurement function and voltage monitoring function into an integrated detection mechanism. By using the same current measurement in the output stage to both characterize the transmitter's operating state and calculate the expected voltage range, the system combines multiple detection functions into a unified approach, improving reliability without proportionally increasing complexity.
Data Source
AI summary
An exemplary embodiment relates to a method for detecting a failure on a differential bus. The method may include: determining an allowed voltage range of the differential bus based on a minimum load and a maximum load; comparing a differential bus voltage with the allowed voltage range; and determining a failure state in case the differential bus voltage is outside the allowed voltage range.