CAN Transceiver Wake-Up Filter for Low-Power Partial Networking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CAN bus systems face challenges in efficiently managing power consumption, particularly in vehicles where not all nodes are active at all times, leading to unnecessary energy usage and reduced driving range.
Innovation Solution
A CAN XL transceiver with a wake-up filter that compares differential voltage signals with multiple threshold levels, including a negative threshold, to detect a predetermined pattern, enabling efficient partial networking by activating only necessary nodes, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all nodes remain active continuously to ensure immediate communication responsiveness, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The transceiver dynamically switches between wake-up and sleep modes based on real-time bus activity detection. The wake-up filter continuously monitors the CAN bus for specific patterns, and when detected, triggers the transceiver to transition from sleep to active mode, ensuring responsive communication only when necessary.
Solution Approach 2:
The system employs periodic wake-up checks where the transceiver wakes up at predetermined intervals to sample the bus for activity patterns, then returns to sleep mode. This periodic monitoring ensures the system remains responsive to communication requests while minimizing power consumption during idle periods.
2Reliability
If nodes wake up frequently to check for communication activity, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The wake-up filter acts as an intermediary that continuously monitors the CAN bus for wake-up patterns without requiring the main transceiver circuitry to be fully active. When a wake-up pattern is detected, the filter triggers the transceiver to wake up, thus separating the low-power monitoring function from the high-power communication function.
3Measurement precision
If the transceiver remains in wake-up mode continuously to detect all communication patterns, then detection accuracy is improved, but power consumption increases
Solution Approach 1:
The detection function is segmented into two parts: a low-power wake-up filter that continuously monitors for specific patterns, and a high-power transceiver that processes communications only when triggered. This segmentation allows accurate pattern detection to be performed by the filter during sleep mode, while the main transceiver remains inactive until needed.
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
The solution allows for reduced power consumption in CAN XL systems by accurately detecting idle periods on the CAN bus, enabling nodes to wake up only when necessary, thus extending the driving range of battery-powered vehicles.
Implementation Method 1
a comparator configured to compare a differential voltage signal from the CAN bus with the negative threshold level
Data Source
Figure 1a~1b
Figure 2~3
Figure 4~5
AI summary
The disclosure relates to a controller area network, CAN, transceiver and a CAN controller. The CAN transceiver is configured to: compare a signal from the CAN bus with a negative threshold level; and provide a wake-up indication to the CAN controller based on the signal matching a predetermined pattern of one or more periods in which the signal is less than the negative threshold level. The CAN controller is configured to provide instructions to transmit a wake-up indication on the CAN bus.