Differential Detection Circuit Self-Diagnosis Using Unequal Capacitors
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Solution Overview
Problem
Existing circuit devices lack the capability for self-diagnosis of detection circuits, particularly in embedded systems like electronic apparatuses and moving objects, where normal operation cannot be assured post-manufacturing, leading to potential faults or performance deterioration during actual use.
Innovation Solution
Incorporating a diagnosis circuit with capacitors of different capacitance values and switch elements to generate a pseudo-desired signal for diagnosing the detection circuit, allowing for self-diagnosis upon power supply and during normal operation, thereby improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manufacturing evaluation methods are used to evaluate the I/V conversion circuit, then the circuit characteristics can be evaluated at the time of manufacturing, but self-diagnosis capability during actual operation cannot be realized
Solution Approach 1:
The patent applies preliminary action by pre-configuring the detection circuit with built-in capacitors of different capacitance values and switch elements that can generate test signals. This allows the circuit to perform self-diagnosis during actual operation without requiring external evaluation equipment, thereby resolving the contradiction between manufacturing evaluation and operational self-diagnosis capability
Solution Approach 2:
The patent implements self-service by enabling the detection circuit to diagnose itself using internal components. The switch elements can connect the built-in capacitors to generate test signals that flow through the I/V conversion circuit, allowing the circuit to evaluate its own characteristics during operation without external intervention, thus achieving self-diagnosis capability
2Measurement precision
If individual I/V conversion circuit evaluation is performed, then the specific circuit characteristics can be assessed, but the entire detection circuit cannot be diagnosed
Solution Approach 1:
The patent applies universality by designing a diagnostic system that can evaluate multiple components of the detection circuit using the same built-in capacitors and switch elements. The test signals generated by the capacitors can flow through various parts of the detection circuit including the I/V conversion circuit, amplifier circuit, and A/D conversion circuit, enabling comprehensive diagnosis of the entire detection circuit rather than just individual components
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
Enables effective self-diagnosis of detection circuits within circuit devices, ensuring normal operation and enhancing reliability by detecting faults or performance deterioration in real-time, even after manufacturing.
Implementation Method 1
a first capacitor which is provided between a first node and a first input node of the first charge/voltage conversion circuit to which the first detection signal is input, and a second capacitor which is provided between the first node and a second input node of the second charge/voltage conversion circuit
Data Source
AI summary
A circuit device includes a detection circuit to which first and second detection signals forming differential signals are input from a physical quantity transducer and a diagnosis circuit. The detection circuit includes first and second charge/voltage conversion circuits. The diagnosis circuit includes a first capacitor which is provided between a first node and a first input node to which the first detection signal is input and a second capacitor which is provided between the first node and a second input node to which the second detection signal is input and has a different capacitor value from the first capacitor. In a diagnosis mode, a diagnosis signal is input to the first node.