Selective CAN Bus Wake-Up via Signal Pattern Detection
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Solution Overview
Problem
Current CAN bus systems require either a separate wake-up line for all control units or wake up all units, including unnecessary ones, due to unwanted bus activity, leading to inefficiencies in power consumption and selective waking up.
Innovation Solution
A method that detects specific signal properties on the CAN bus to initiate a wake-up process, using multiple patterns for group and individual node waking, allowing for selective and efficient activation of only needed control devices, with a two-stage process to enhance reliability and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate wake-up line is provided for all control units, then reliable selective waking up is achieved, but device complexity and wiring overhead increase
Solution Approach 1:
The patent merges the wake-up function with the existing CAN bus communication lines. Instead of using separate dedicated wake-up lines, the system utilizes the standard CAN bus for both communication and wake-up purposes. The detection means monitors signal properties on the existing bus lines to identify wake-up requests, thereby eliminating the need for additional wiring while maintaining reliable selective wake-up capability.
Solution Approach 2:
The CAN bus lines are given multi-functionality by serving both as communication channels and wake-up triggers. The detection means enables the bus system to universally handle both data transmission and wake-up signaling through the same infrastructure, reducing device complexity while preserving the ability to selectively wake up individual nodes or groups based on specific signal patterns.
2Device complexity
If wake-up via bus is used for all control units, then wiring complexity is reduced, but power consumption increases due to unnecessary wake-ups
Solution Approach 1:
The patent segments the wake-up response by control unit through the use of specific signal properties and patterns. Each control unit is configured to recognize particular signal characteristics (such as specific dominant bit patterns, edge changes, or signal levels) that correspond to wake-up requests intended for that unit or its group. This segmentation enables selective wake-up via the shared bus without requiring dedicated lines, thereby reducing power consumption by waking up only necessary units while maintaining the wiring simplicity of bus-based communication.
3Use of energy by moving object
If standard CAN transceiver sleep mode is used, then power consumption is reduced, but selective wake-up capability is lost
Solution Approach 1:
The patent introduces a detection means as an intermediary component that bridges the gap between the low-power sleep mode and selective wake-up capability. This detection means continuously monitors the CAN bus for specific signal properties while consuming minimal power, and selectively triggers wake-up only when relevant patterns are detected. The detection means acts as a mediator that enables the transceiver to remain in power-saving mode while still providing adaptive selective wake-up functionality through intelligent signal pattern recognition.
4Measurement precision
If multiple signal patterns are defined for group and individual wake-up, then wake-up precision is improved, but detection complexity increases
Solution Approach 1:
The patent applies local quality by assigning specific signal properties to different wake-up scenarios. Different signal characteristics (such as specific dominant bit positions, particular edge change patterns, or defined signal level combinations) are locally associated with different wake-up targets (individual nodes or groups). This localized signal property assignment enables precise wake-up differentiation while keeping the detection logic relatively simple, as each node only needs to recognize its specifically assigned patterns rather than analyzing all possible signal variations.
Data Source
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AI summary
The invention relates to a device for waking up consumers in a CAN bus system, according to which detection means detect at least one predetermined signal characteristic of signals that are communicated in the bus system and depending on the behaviour of the detected predefined characteristic or characteristics, a subsequent wake-up operation is initiated. The invention is characterised in that at least two courses, patterns or sequences of one of the at least one signal characteristics are defined, one course, or pattern or sequence being used to wake-up a group of consumers and a second course, or second pattern, or second sequence being used to wake-up individual consumers.