Multiplexed A/D Converter Fault Detection Using Pull-Down Modes
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Solution Overview
Problem
Existing A/D conversion devices face challenges in detecting anomalies of the A/D converter itself and connected devices without increasing the number of A/D converters or adding additional circuits, and they lack effective failure diagnosis functions.
Innovation Solution
An A/D conversion device with a control section that operates in multiple modes to independently manage analog signal output to the A/D converter, allowing for anomaly detection by switching circuits and using a resistor to simulate normal and abnormal conditions, thereby enabling failure diagnosis without additional circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple A/D converters are used to handle increasing analog signals, then the number of input information items increases, but the device complexity and cost increase
Solution Approach 1:
The patent applies multi-functionality by enabling a single A/D converter to handle multiple input signals through time-division multiplexing. The switching circuit connects multiple analog signal sources to the single A/D converter sequentially, allowing one device to perform the function of multiple converters while reducing device complexity and cost
2Adaptability or versatility
If a switching circuit is added to select multiple input signals, then the number of input information items increases, but the reliability decreases due to potential switch failures
Solution Approach 1:
The patent implements feedback mechanisms through anomaly detection circuits that continuously monitor the switching circuit and A/D converter operation. When a switch failure or anomaly is detected, the system generates error signals and can switch to backup pathways, ensuring reliable operation despite the presence of switching components
3Reliability
If an additional failure diagnosis circuit is provided, then the reliability improves through anomaly detection, but the device complexity increases
Solution Approach 1:
The patent merges the failure diagnosis function with the existing A/D converter circuitry. The anomaly detection circuit shares components and control logic with the main conversion system, integrating reliability monitoring into the existing structure rather than adding completely separate diagnostic equipment, thus improving reliability while minimizing additional complexity
4Device complexity
If a single A/D converter is used with switching circuits, then the device complexity is reduced, but the measurement precision may decrease due to switching transitions
Solution Approach 1:
The patent applies preliminary action by stabilizing the analog signal at each switching position before initiating the A/D conversion process. The system allows sufficient settling time for the signal to reach a stable state after switching, ensuring that conversion begins only when the signal is steady, thereby maintaining measurement precision despite the presence of switching transitions
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
This solution allows for the conversion of multiple analog signals to digital signals without increasing A/D converters and adds a failure diagnosis function with a simple additional circuit, enhancing the reliability of signal conversion and anomaly detection.
Implementation Method 1
a third mode in which to output none of the analog electricity quantities of the objects and cause the output to the A/D converter to be pulled down by a resistor
Data Source
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AI summary
A first mode in which to output analog electricity quantities of objects (4, 5) one by one independently to an A/D converter (1), a second mode in which to output none of the analog electricity quantities of the objects (4, 5), a third mode in which to output none of the analog electricity quantities of the objects (4, 5) and cause the output to the A/D converter (1) to be pulled down by a pull-down resistor (10), and a fourth mode in which to output to the A/D converter (1) a plurality of the analog electricity quantities of the objects (4, 5) at the same time, are caused to be generated, thus acquiring the A/D conversion values of the objects (4, 5) individually when in the first mode, and detecting an anomaly of the A/D converter (1) itself or a device connected to the A/D converter (1) when in the second mode to the fourth mode.