Sensor Diagnostic Circuits for Fault Detection and Safe Operation
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Solution Overview
Problem
Conventional sensors are insufficient for ensuring increased safety, particularly in vehicle applications, as they lack effective diagnostic capabilities to detect abnormalities and ensure reliable operation.
Innovation Solution
A sensor system comprising a detection signal outputting element, a drive circuit, a detection circuit with synchronous demodulation, a processing circuit, and diagnostic circuits that monitor and diagnose signal abnormalities, enhancing safety through redundant signal paths and error detection mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sensor diagnostic methods are used, then device complexity is reduced, but reliability is insufficient
Solution Approach 1:
The diagnostic function is segmented into multiple independent diagnostic circuits, each responsible for monitoring specific signal paths. The first diagnostic circuit monitors the signal path from the element through the drive circuit and detection circuit, while the second diagnostic circuit monitors the signal path through the processing circuit. This segmentation allows comprehensive monitoring without requiring a single complex diagnostic system.
Solution Approach 2:
The diagnostic circuits perform preliminary monitoring of signal paths to detect abnormalities before they affect sensor operation. By continuously monitoring signals at multiple points in advance, the system can identify wire breaks or component failures early and output error signals before critical failures occur, ensuring safety without interrupting normal sensor function.
2Reliability
If multiple diagnostic circuits are added, then reliability is improved, but device complexity increases
Solution Approach 1:
The diagnostic circuits are designed with multi-functionality to reduce overall system complexity. Each diagnostic circuit can monitor multiple signal paths and detect various types of abnormalities (wire breaks, component failures). The first diagnostic circuit monitors both the drive signal path and detection signal path, while the second diagnostic circuit monitors the processing signal path. This universal monitoring capability reduces the need for separate dedicated monitoring circuits for each signal path.
Solution Approach 2:
The diagnostic circuits monitor the sensor's own internal signal paths without requiring external testing equipment or additional sensors. The system uses its existing signal paths and components to perform self-diagnosis, where the first diagnostic circuit monitors signals within the drive and detection circuits, and the second diagnostic circuit monitors the processing circuit signals. This self-service approach improves reliability without requiring external diagnostic systems.
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 sensor system improves safety by providing robust diagnostic capabilities, detecting abnormalities, and maintaining sensor operation even in the event of faults, such as wire breaks, thereby ensuring reliable performance.
Implementation Method 1
a detection circuit including an amplifier that amplifies the detection signal
Implementation Method 2
a first synchronous demodulation circuit that performs synchronous demodulation on a signal from the amplifier
Data Source
AI summary
A sensor is provided including: an element outputting detection signals according to magnitude of physical quantity; a drive circuit outputting a driving signal to the element and receiving a monitor signal from the element; a detection circuit that includes amplifiers amplifying the detection signals and a first synchronous demodulation circuit performing synchronous demodulation on a signal from the amplifier, receives the detection signals, and outputs a physical quantity signal according to the physical quantity; a processing circuit processing a signal from the first synchronous demodulation circuit; a first diagnostic circuit that receives a signal into the processing circuit and a signal from the processing circuit, and outputs a first error signal when abnormalities occur in the processing circuit; and a second diagnostic circuit that outputs a diagnostic signal to the first diagnostic circuit, instead of the signal into the processing circuit or instead of the signal from the processing circuit.