Redundant Diode Supply Path Diagnostics in Vehicle Control Units
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Solution Overview
Problem
Control units in motor vehicles face challenges in preventing electrical interference from propagating to emergency supply lines, which can cause cascading failures in other connected units, especially during defects or overvoltage conditions, and existing diagnostic methods cannot detect diode failures in real-time operation.
Innovation Solution
The implementation of two series-connected unidirectional blocking elements in the current paths of supply connections, along with a diagnostic circuit that checks the blocking effect using a predetermined diagnostic routine, ensures continuous protection against electrical reactions by maintaining the blocking effect even if one element fails, and a diagnostic network with switching elements to verify the blocking effect of both elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single unidirectional blocking element (diode) is used in the current path of an emergency supply connection to prevent electrical reactions, then protection against interference propagation is provided, but the system cannot detect diode failures in real-time operation
Solution Approach 1:
The patent divides the single blocking function into two separate unidirectional blocking elements (D1 and D2) connected in series. This segmentation allows the system to maintain protection functionality while enabling diagnostic capability - if one diode fails, the other continues to provide protection and the failure can be detected through monitoring the voltage at the intermediate connection point.
Solution Approach 2:
The patent introduces an intermediate connection point (K1) between the two diodes as a mediator that enables diagnostic functionality. This intermediate point serves as a monitoring location where the control unit can measure voltages to detect failures in either diode, without compromising the primary protection function against electrical reactions.
2Reliability
If two series-connected unidirectional blocking elements are used in the current path, then continuous protection against electrical reactions is maintained even if one element fails, but the device complexity increases
Solution Approach 1:
The patent makes the diagnostic circuit multi-functional by using it to monitor both diodes (D1 and D2) through a single intermediate connection point (K1). The same monitoring infrastructure serves dual purposes: detecting failures in either diode while both diodes continue to provide protection, thereby reducing the relative complexity increase.
Solution Approach 2:
The patent implements redundancy by placing two unidirectional blocking elements in series, where the second element acts as a backup for the first. This beforehand cushioning ensures that if one diode fails, the system continues to provide protection against electrical reactions, maintaining reliability without requiring immediate system shutdown.
3Reliability
If blocking elements are used to prevent electrical reactions in emergency supply lines, then other control units connected to the emergency supply line are protected from interference, but the current paths become more complex requiring additional diagnostic routines
Solution Approach 1:
The patent implements feedback mechanisms where the control unit continuously monitors the voltage at the intermediate connection point (K1) between the two diodes. This feedback allows the system to detect failures in either diode and trigger appropriate diagnostic routines, ensuring that protection functionality is maintained while providing visibility into the health of the blocking elements.
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 effectively prevents electrical reactions from propagating to supply lines, ensuring continuous operation and reducing the likelihood of double faults, thereby enhancing the reliability of control units in motor vehicles, especially in autonomous driving systems.
Implementation Method 1
two series-connected unidirectional blocking elements in the current paths of supply connections
Data Source
AI summary
A control unit for a motor vehicle, having a supply connection for receiving a supply voltage from a supply line needing to be secured against a reaction from the control unit, wherein to protect against the reaction there is provision in a current path of the supply connection for a unidirectional first blocking element, and a diagnostic circuit is configured to check the blocking effect thereof by a predetermined diagnostic routine. An additional, second unidirectional blocking element is connected in series with the blocking element in the current path of the supply connection, wherein the first and the second blocking element each provide for a unidirectional flow of current to the device circuit, and the diagnostic circuit is configured to use the diagnostic routine to also check the blocking effect of the second blocking element.