Network Switching Circuit for LIN Node Addressing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In master-slave type networks like LIN, addressing multiple identical slave nodes efficiently while preventing signal interference and ensuring reliable communication within a specific voltage range is challenging, especially in noisy environments and during node addressing processes.
Innovation Solution
An integrated switch is implemented at each network node to selectively connect or disconnect nodes from the communication bus, using MOS-based transistors that prevent signal passing when not conducting, allowing unique node addressing and maintaining EMI performance within the supply voltage range of 7V to 18V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex protocols and additional communications circuits are used to implement detailed LIN protocol communications, then communication functionality is improved, but device complexity and susceptibility to failure increase
Solution Approach 1:
The microcontroller unit is designed to perform multiple functions: it acts as both a LIN protocol controller and a USB device controller, eliminating the need for separate dedicated hardware circuits for each protocol. The MCU handles LIN messaging, USB communication, and node addressing functions through software implementation, reducing overall device complexity while maintaining full communication capabilities.
Solution Approach 2:
The patent replaces complex hardware-based LIN protocol implementation with software-based processing on a general-purpose microcontroller. Instead of using dedicated LIN controller hardware with separate circuits for protocol handling, the MCU executes firmware that implements the LIN protocol stack, substituting mechanical/electrical complexity with programmable logic.
2Reliability
If switches are used to prevent signal passing between nodes during addressing, then addressing reliability is improved, but signal transmission capability may be compromised outside voltage range
Solution Approach 1:
The switch circuit parameters are specifically designed to operate within the automotive voltage range of 7V to 18V. The MOSFET-based switches are selected and configured to maintain proper on/off states across this voltage range, ensuring reliable node addressing while accommodating the full operating voltage spectrum of automotive systems.
Solution Approach 2:
The switch circuit acts as an intermediary element between the MCU and other LIN nodes, controlled by the MCU to enable or disable signal transmission. This intermediary switch provides precise control over signal flow during addressing operations while maintaining system-wide voltage compatibility through proper component selection.
3Object-affected harmful factors
If MOS-based transistors are used as switches to control signal flow, then EMI performance is improved, but switching control complexity increases
Solution Approach 1:
The MOS-based switch control is merged with the existing MCU operational modes. The MCU integrates switch control logic into its normal operation sequence, combining the switch driving function with the LIN protocol state machine and USB communication handling, thereby avoiding additional control circuitry while achieving low EMI performance.
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 efficient node addressing in LIN networks, preventing signal interference and ensuring reliable communication between master and slave nodes, even in noisy conditions, by using MOS-based transistors to control signal flow, allowing for unique addressing of each slave node within the specified voltage range.
Implementation Method 1
An integrated switch is implemented at each network node to selectively connect or disconnect nodes from the communication bus, using MOS-based transistors that prevent signal passing when not conducting
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Various exemplary aspects are directed to apparatuses and methods involving switches communicatively-coupled on a bus where one or more of the switches operate to block signals from passing through the switch in a first mode, and to pass signals through the switch in a second mode. A logic circuit is responsive to addressing information received in the first mode, by storing and configuring the apparatus with the address information. The logic circuit ignores address information received in the second mode (e.g., does not reconfigure the apparatus with address information received in the second mode).