Diode-Based Galvanic Isolation for Motor Vehicle Controller Communication
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Solution Overview
Problem
Existing motor vehicle systems require galvanic isolation to prevent fault currents between master and slave controllers operating at different reference voltages, which is expensive and space-intensive.
Innovation Solution
A communication line with a diode between the master and slave controllers, where the master operates at a first reference voltage and the slave at a second, allowing for fault current prevention without galvanic isolation by using a pull-up resistor and electric switches to manage voltage potentials, enabling communication without the need for separate power and ground connections at the slave controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic isolation is used to prevent fault currents between master and slave controllers operating at different reference voltages, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
A diode is introduced as an intermediary component in the communication line between master and slave controllers. The diode acts as a one-way valve for current flow, allowing communication signals to pass while blocking fault currents from flowing back to the master controller. This simple intermediary component eliminates the need for complex galvanic isolation while maintaining reliability.
Solution Approach 2:
The patent extracts the fault current prevention function from the complex galvanic isolation system and implements it through a simple diode component in the communication line. By separating the communication function from the isolation function, the system achieves fault current protection without requiring expensive and space-intensive galvanic isolation hardware.
2Reliability
If galvanic isolation is implemented to protect against ground loss, short circuits, and reversed polarity, then reliability is improved, but installation space increases
Solution Approach 1:
The patent replaces expensive and space-consuming galvanic isolation components with inexpensive diode components that can be easily integrated into the communication line. The diode provides the necessary protection function at a fraction of the cost and space requirements of traditional galvanic isolation solutions.
3Reliability
If separate power supply lines and ground connections are provided for each slave controller, then reliability is improved, but device complexity and installation cost increase
Solution Approach 1:
The patent merges the power supply and communication functions into a single communication line. By using the same communication line for both power delivery and data communication, the system eliminates the need for separate power supply lines and ground connections at each slave controller, reducing complexity while maintaining reliability through the diode protection.
Solution Approach 2:
The communication line is designed to serve multiple functions: it provides both communication signals and power delivery to slave controllers. The diode component enables this multi-functional use by ensuring that power and signals can flow to the slave controller while preventing reverse current flow that could cause faults.
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 allows for economical and compact manufacturing by eliminating the need for galvanic isolation, enabling reliable communication between controllers with different reference voltages while preventing fault currents.
Implementation Method 1
a diode is provided in the communication line which prevents a current flow from the second transceiver unit in the direction of the first transceiver unit
Data Source
AI summary
An arrangement for a motor vehicle includes a master controller and a slave controller that use different reference-earth voltages and respectively comprise a transmission and a reception unit for shared data interchange. The transmission and reception units are connected to one another via a shared communication line. The communication line contains a diode that prevents a flow of current from the slave controller to the master controller. The master controller contains a pull-up resistor via which the shared communication line can be connected to a first reference-earth potential of the reference-earth voltage of the master controller.