Load Drive Circuit Self-Test Using Pseudo Abnormality Signals
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Solution Overview
Problem
Existing load drive circuits in vehicles lack a method to quickly detect diagnosis circuit failures during vehicle operation, leading to potential breakdowns due to undetected abnormalities in the load drive circuit, which can go unnoticed by both the vehicle control system and passengers.
Innovation Solution
Inputting a pseudo abnormality signal into the diagnosis circuit allows for the determination of its failure without affecting load drive control, enabling timely detection and notification of failures through warning systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diagnosis circuit continuously monitors load abnormality during vehicle operation, then the reliability of load drive control is improved, but the ability to detect diagnosis circuit failure itself is worsened
Solution Approach 1:
The patent applies preliminary action by inputting a pseudo abnormality signal to the diagnosis circuit before actual abnormality can occur. This allows the system to proactively test whether the diagnosis circuit is functioning properly by simulating an abnormal condition and checking if the circuit correctly detects it, thereby determining the operational status of the diagnosis circuit itself.
Solution Approach 2:
The patent uses a pseudo abnormality signal as an intermediary to indirectly assess the health of the diagnosis circuit. Instead of directly monitoring the diagnosis circuit's internal state, the system introduces a test signal that mediates between the control system and the diagnosis circuit, allowing failure detection without interfering with normal load drive operations.
2Speed
If the system tests diagnosis circuit functionality frequently, then the detection speed of diagnosis circuit failure is improved, but the disruption to normal vehicle operation is worsened
Solution Approach 1:
The system employs periodic action by scheduling pseudo abnormality signal inputs at specific intervals rather than continuously. The control circuit determines appropriate timing for these test signals, ensuring that diagnosis circuit functionality is verified regularly while minimizing disruption to normal vehicle operations. This periodic testing approach balances failure detection speed with operational continuity.
Solution Approach 2:
The patent applies dynamics by making the testing frequency and timing adaptable based on system state. The control circuit dynamically adjusts when to input pseudo abnormality signals, allowing more frequent testing when the system is idle or in safe states, and reducing testing frequency during critical operations, thereby optimizing both detection speed and operational disruption minimization.
Data Source
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AI summary
A load drive circuit incorporated into an onboard electronic control device, the load drive circuit housing a diagnosis circuit for diagnosing load abnormalities, wherein diagnosis circuit failures are detected without affecting load drive control. When a failure has occurred in the diagnosis circuit, vehicle operation is not affected because the diagnosis circuit does not have a function for controlling the vehicle, and there may be cases in which occupants riding in the vehicle do not notice the failure. Additionally, when a failure has occurred in the diagnosis circuit, the occurrence of the failure cannot be detected even by a vehicle control system as long as there is no function for detecting occurrences of failure in the diagnosis circuit. Specifically, when a failure has occurred in the diagnosis circuit, there is a possibility that the failure is unrecognizable to occupants and undetectable by a vehicle control system. When there is no need for the diagnosis circuit to diagnose load abnormalities, a determination of whether or not the diagnosis circuit is failing is made by sending a pseudo abnormality signal to the diagnosis circuit and confirming whether the diagnosis circuit can detect the sent pseudo abnormality signal as a failure.