Sensor Fault Detection via Segmented Switching Circuit
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Solution Overview
Problem
Conventional fault detection systems in sensors are unable to precisely identify faulty sensing elements or bond wires, leading to impaired sensor functionality and unreliable output.
Innovation Solution
A sensing circuit with a switching circuit, a test circuit, and a converter is used to selectively couple sensing and test elements during normal and fault diagnosis modes, allowing for precise detection of faults in sensing elements and bond wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fault detection systems are used, then the system structure remains simple, but the measurement precision of fault location is insufficient
Solution Approach 1:
The sensor is divided into multiple independent sensing elements (first sensing element and second sensing element), each capable of being individually tested. The bond wires are segmented into multiple separate connections (first bond wire and second bond wire), allowing independent fault detection for each segment. This segmentation enables precise localization of faults without requiring complex system restructuring.
Solution Approach 2:
A test circuit is introduced as an intermediary component between the sensing elements/bond wires and the main reading circuit. The test circuit includes test voltage sources and measurement circuits that can be selectively activated to test specific sensing elements and bond wires without interfering with normal sensor operation. This intermediary structure enables precise fault detection while maintaining system simplicity.
2Reliability
If no fault detection capability is implemented, then the device complexity is low, but the reliability of sensor output is insufficient
Solution Approach 1:
The test circuit is designed to perform multiple functions: testing the first sensing element, testing the second sensing element, testing the first bond wire, and testing the second bond wire. By using a universal test circuit structure that can selectively test different components, the patent achieves high reliability without proportionally increasing complexity. The same test circuit infrastructure serves all fault detection purposes.
Solution Approach 2:
The system performs fault detection tests during manufacturing or initialization phases to identify and isolate faulty sensing elements or bond wires before they affect normal operation. This preliminary action allows the system to maintain high reliability by pre-identifying faults, while the complexity is confined to the test circuit structure rather than the main sensor functionality.
3Measurement precision
If all sensing elements are tested simultaneously, then the fault detection speed is fast, but the measurement precision of individual faulty elements is lost
Solution Approach 1:
The test circuit employs dynamic switching mechanisms that can selectively activate different test paths based on the suspected faulty component. The system can dynamically reconfigure the test circuit to test specific sensing elements or bond wires individually, allowing precise identification of faulty elements while maintaining efficient detection speeds through targeted testing rather than simultaneous testing of all components.
Data Source
AI summary
A sensing circuit is coupled to a sensor comprising first and second sensing elements. The sensing circuit detects changes in physical parameters by determining change in attributes of first and second sensing elements. The sensing circuit may include a switching circuit, first and second test elements, and a converter. During a normal mode, the switching circuit couples the first and second sensing elements to the converter to generate a first parameter value. During a fault diagnosis mode, the switching circuit couples one of (i) a first test element and the second sensing element and (ii) a second test element and the first sensing element to the converter to generate a second parameter value. The second parameter value is compensated to obtain a third parameter value that is further compared with the first parameter value to obtain a differential value. Based on the differential value, faults in the sensor are detected.