CAN Transceiver Wake-Up Detection for Partial Networking
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Solution Overview
Problem
In-vehicle network busses, such as CAN, face challenges in efficiently managing power consumption due to the need for continuous operation of all nodes, which affects the driving range of battery-powered vehicles, especially when not all nodes are actively required.
Innovation Solution
A CAN XL transceiver and controller system that compares signals with a negative threshold level to provide a wake-up indication, allowing for partial networking by activating only necessary nodes, thereby reducing power consumption and implementing efficient wake-up mechanisms using a predetermined pattern of signal periods below the negative threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all nodes operate continuously to maintain network functionality, then network reliability is improved, but power consumption increases
Solution Approach 1:
The transceiver dynamically switches between different operational states (low-power sleep mode and active mode) based on network conditions. The wake-up mechanism allows the transceiver to transition from sleep mode to active mode when a wake-up indication is detected, and return to sleep mode when the network is idle, optimizing power consumption while maintaining network reliability
Solution Approach 2:
The transceiver monitors the CAN bus for wake-up indications even while in low-power mode. By detecting the predetermined pattern of signal periods below the negative threshold before fully activating, the system prepares for network activity in advance, ensuring rapid response while minimizing the time spent in high-power state
2Use of energy by moving object
If nodes are activated selectively to reduce power consumption, then power efficiency is improved, but network responsiveness may deteriorate
Solution Approach 1:
The wake-up indication uses a predetermined pattern of periodic signal periods below the negative threshold level. This periodic structure allows the transceiver in low-power mode to efficiently detect network activity through rhythmic signal monitoring, enabling rapid wake-up activation without continuous operation, thus maintaining responsiveness while improving power efficiency
Solution Approach 2:
The system replaces continuous mechanical operation (continuous transceiver activation) with an event-triggered mechanism. The transceiver is activated only when a specific electrical signal pattern (wake-up indication) is detected on the CAN bus, substituting constant power consumption with selective event-driven activation that maintains network responsiveness
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 enables reduced power consumption by selectively activating nodes only when needed, enhancing the efficiency and longevity of battery-powered vehicles by implementing a reliable and efficient partial networking scheme within the CAN XL system.
Implementation Method 1
a comparator configured to compare a differential voltage signal from the CAN bus with the negative threshold level
Data Source
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.