Sensor Readout Redundancy-Checking Circuit
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Solution Overview
Problem
Existing sensor systems, particularly impedance-based sensors like Wheatstone bridges, face challenges in fully utilizing internal redundancy for enhanced reliability due to limitations in existing fault detection methods that fail to detect mismatch conditions effectively, leading to potential undetected errors.
Innovation Solution
A difference measurement circuit with switching units and redundancy testing circuitry that dynamically reconfigures the sensor unit by rotating and flipping the bridge configurations to evaluate the similarity or deviation of measurement signals, allowing for a comprehensive redundancy test through symmetrical excitation and advanced signal processing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors are used to measure a same physical parameter, then reliability is improved, but cost increases significantly
Solution Approach 1:
The patent segments the redundancy function from the sensor level to the readout circuit level. Instead of using multiple complete sensors, the invention divides the sensor array into multiple sensing elements that share a common readout circuit, enabling redundancy checking through signal processing rather than hardware duplication.
Solution Approach 2:
The readout circuit is designed to perform multiple functions: normal measurement mode and redundancy check mode. The same circuit infrastructure is used for both sensing operations and fault detection, eliminating the need for separate redundant hardware while maintaining reliability functions.
2Device complexity
If a simple common-mode voltage check is used for fault detection, then device complexity is reduced, but measurement precision deteriorates due to undetected mismatch conditions
Solution Approach 1:
The patent introduces dynamic reconfiguration of the sensor array during operation. By periodically changing the connection topology and measurement configurations, the system creates varying measurement conditions that expose mismatches which would remain hidden under static operation. This dynamic approach enables comprehensive fault detection without adding complex dedicated test hardware.
Solution Approach 2:
The system changes measurement parameters such as excitation patterns, readout configurations, and signal processing methods to detect faults. By varying these parameters and observing changes in measurement outputs, the system can identify mismatch conditions that would be invisible under fixed measurement conditions.
3Measurement precision
If dynamic reconfiguration and comprehensive redundancy testing are implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the redundancy checking functions with the normal measurement readout circuitry. The same switches, amplifiers, and signal paths are used for both regular sensing and fault detection, eliminating the need for separate test hardware and minimizing the increase in device complexity.
Solution Approach 2:
The system performs self-diagnosis by using its own measurement infrastructure to detect faults. The readout circuit automatically monitors its own operation and detects mismatches through intelligent signal processing, eliminating the need for external test equipment or additional monitoring hardware.
Data Source
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AI summary
The present invention provides a difference measurement circuit (60) comprising a first port (P1, P1') and a second port (P2, P2') for connection to a first set of nodes (A, B) and a second set of nodes (C, D) of a sensor unit. The circuit (60) further comprises switching units (61, 62) for switching excitation signals emanating from excitation nodes (C', D') from being applied to the first set of nodes (A, B) via the first port (P1, P1') to being applied to the second set of nodes (C, D) via the second port (P2, P2') and for switching differential measurement signals measured at sensing nodes (A', B') from being obtained from the second set of nodes (C, D) via the second port (P2, P2') to being obtained from the first set of nodes (A, B) via the first port (P1, P1'). The present invention also provides a corresponding method. The circuit (60) further comprises redundancy testing circuitry for evaluating the similarity or deviation between measurement signals obtained in different states of the switching units (61, 62).