Sensor Diagnostic Circuit Using Redundant Signal Path Switching
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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 output 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 the sensor can detect basic operational status, but the safety and reliability are insufficient for increased sensor safety requirements
Solution Approach 1:
The diagnostic system is segmented into multiple independent diagnostic circuits (first diagnostic circuit, second diagnostic circuit, third diagnostic circuit) that can independently monitor different aspects of sensor operation. This segmentation allows comprehensive safety monitoring while maintaining modular complexity management.
Solution Approach 2:
A switch circuit is introduced as an intermediary component that can selectively connect different signal paths to the first diagnostic circuit. This intermediary enables flexible diagnostic configurations and signal routing, improving reliability without permanently increasing structural complexity.
2Reliability
If multiple diagnostic circuits are added to improve safety, then sensor reliability increases, but the device complexity and circuit structure become more complex
Solution Approach 1:
The first diagnostic circuit is designed with multi-functionality, capable of receiving and processing multiple different input signals (first signal, second signal, third signal) through the switch circuit. This universal diagnostic approach allows a single circuit structure to perform multiple diagnostic functions, improving reliability without proportionally increasing circuit complexity.
Solution Approach 2:
The diagnostic system uses signal copying and redundancy by creating multiple diagnostic pathways that monitor the same or different aspects of sensor operation. The switch circuit enables selective copying of signals to the diagnostic circuit, allowing comprehensive monitoring while managing complexity through shared circuitry.
3Measurement precision
If redundant signal paths and error detection mechanisms are implemented, then abnormality detection capability improves, but the device complexity increases
Solution Approach 1:
The switch circuit introduces dynamic configurability to the diagnostic system, allowing selective connection of different signal paths based on diagnostic needs. This dynamic approach enables precise abnormality detection by routing appropriate signals to the diagnostic circuit only when needed, improving detection accuracy without permanently maintaining complex circuit structures.
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.