Output Stage Fault Detection via Periodic State Switching
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Solution Overview
Problem
Existing output stage control systems for loads in automotive applications face challenges in simultaneously detecting all possible fault states, such as short circuits to ground or battery and cable breaks, without disrupting the load's operation or requiring additional hardware.
Innovation Solution
The method involves switching the output stage between two states for predefined durations to enable fault state checks, using test pulses to determine fault conditions like short circuits or cable breaks without affecting the load's operation, allowing continuous monitoring without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output stage operates continuously in one switching state to maintain load operation, then the load operation is uninterrupted, but fault states cannot be checked
Solution Approach 1:
The patent implements periodic switching between first and second switching states at predefined times. During the first switching state, the output stage connects the load to the supply voltage for normal operation. During the second switching state, the output stage disconnects the load to enable fault detection. This periodic action allows both continuous load operation and regular fault checking without requiring additional hardware.
2Reliability
If the output stage switches states to check for fault states, then comprehensive fault detection is enabled, but the load operation may be disrupted
Solution Approach 1:
The patent performs fault detection during brief intervals when switching between operating states. By checking for fault states (such as short circuits to ground or battery, and cable breaks) during these transition periods before the next load operation cycle begins, the system ensures comprehensive monitoring without disrupting the actual load operation. The predefined switching times ensure that fault checks occur at optimal moments.
3Reliability
If additional hardware is added to enable continuous fault monitoring, then fault detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the output stage multi-functional by enabling it to perform both normal load control and fault detection using the same hardware components. The control unit utilizes the existing switching transistors and circuitry to alternate between operational modes, eliminating the need for separate dedicated fault detection hardware. This universal approach achieves continuous monitoring capability while maintaining simple device architecture and avoiding additional cost.
Data Source
AI summary
A method for checking an output stage for controlling a load, wherein the output stage for controlling the load can be switched to a first switching state or to a second switching state. In the first switching state, a check for a first fault state may be carried out; in the second switching state, a check for a second fault state may be carried out; when the output stage is operated in the first switching state, the output stage is switched to the second switching state for a first control duration, the check for the second fault state is performed, and the output stage is switched back to the first switching state after the first control duration.