LIN Bus Galvanic Isolation Using Antiparallel Optocouplers
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Solution Overview
Problem
Existing galvanic isolation devices for LIN bus systems in motor vehicles require significant space and are costly due to the use of multiple microcontroller inputs and unused integrated LIN transceivers.
Innovation Solution
A galvanic isolation device using two optocouplers arranged in antiparallel configuration with diodes and external amplifier circuits, allowing bidirectional signal transmission without feedback, integrated within a microcontroller, and utilizing pull-up resistors to maintain signal levels, thereby reducing space and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a LIN transceiver and digital isolator are used for galvanic isolation, then protection against overvoltage and ground offset is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the galvanic isolation function with the LIN transceiver functionality into a single integrated device. The optocoupler is integrated directly into the LIN transceiver chip, eliminating the need for separate digital isolator components. This merging reduces device complexity while maintaining protection against overvoltage and ground offset through the optocoupler's galvanic isolation capability.
Solution Approach 2:
The LIN transceiver is designed to perform multiple functions: signal transmission/reception on the LIN bus, galvanic isolation via integrated optocoupler, and interface to the microcontroller. This multi-functionality eliminates the need for dedicated digital isolator components, reducing overall system complexity while maintaining reliability.
2Reliability
If a LIN transceiver and digital isolator are used for galvanic isolation, then protection against reverse current is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges the galvanic isolation function with the LIN transceiver into a single integrated component. The optocoupler is fabricated on the same chip as the LIN transceiver, reducing component count and assembly costs. This integration maintains reverse current protection while lowering manufacturing expenses through reduced part count and simplified assembly processes.
Solution Approach 2:
The optocoupler is nested within the LIN transceiver chip structure, with the light-emitting element and light-receiving element integrated into the same semiconductor substrate. This nesting approach reduces packaging costs and assembly complexity while maintaining the galvanic isolation function for reverse current protection.
3Ease of operation
If two microcontroller inputs are used for bidirectional communication, then signal transmission is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic direction control for signal transmission. A single microcontroller input pin can dynamically switch between transmitting and receiving modes based on the communication direction required. The LIN transceiver internally manages the bidirectional communication protocol, allowing flexible signal transmission without requiring two dedicated input pins, thus reducing device complexity while maintaining operational flexibility.
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 provides effective, cost-effective, and space-efficient galvanic isolation for LIN bus systems, ensuring reliable signal quality and compatibility with automotive sector requirements, while minimizing quiescent current and feedback issues.
Implementation Method 1
each having a light-emitting element and a light-receiving element
Implementation Method 2
each having a light-emitting element and a light-receiving element
Data Source
AI summary
The present disclosure relates to a galvanic isolation device or a bidirectional connecting line of a LIN bus system with two optocouplers arranged in antiparallel, each having a light-emitting element and a light-receiving element, wherein the galvanic isolation device is connectable to a LIN bus via a first signal connection and to a microprocessor via a second signal connection, wherein each signal connection is connected to the respective light-emitting element of an optocoupler, and wherein a diode is connected in antiparallel to the light-emitting element, such that, when a low signal level is applied to one of the signal connections, the signal level at the other signal connection is also low, without the signal being fed back.