A/D Converter Input Checking Circuit Using Dual Derived Signals
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Solution Overview
Problem
Existing switching circuits for checking analog input circuits of A/D converters are vulnerable to faults and electromagnetic interference, leading to processing errors, as they lack independent signal processing and fault detection mechanisms.
Innovation Solution
A switching circuit that generates two independent derived signals from an analog input signal, which are then compared using a comparator circuit to check if deviations lie within a tolerance range, with the option to introduce a defined error state for fault detection, utilizing amplifiers and resistors to derive these signals and a microcontroller for evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single analog input circuit is used for A/D conversion, then the device complexity is low, but the reliability is insufficient due to vulnerability to faults and electromagnetic interference
Solution Approach 1:
The patent divides the single analog input circuit into two separate signal derivation paths. The analog input circuit generates both a first derived signal and a second derived signal from the same analog input variable, allowing independent processing and comparison of these two signals to detect faults and electromagnetic interference.
Solution Approach 2:
The patent creates a redundant copy of the signal processing path by generating two derived signals through separate amplifiers. These copied signal paths are processed independently and then compared, enabling fault detection without significantly increasing overall system complexity.
2Reliability
If two independent derived signals are generated and processed separately, then the reliability and fault detection capability are improved, but the device complexity increases
Solution Approach 1:
The patent merges the two separately processed derived signals at the comparator circuit stage. By combining the first derived signal and the second derived signal for comparison, the system achieves reliable fault detection while consolidating the processing architecture to manage complexity.
Solution Approach 2:
The comparator circuit serves multiple functions: it compares the two derived signals, detects deviations beyond tolerance ranges, identifies faults in the analog input circuit, and generates error signals. This multi-functionality reduces the need for separate dedicated circuits for each function.
3Measurement precision
If a comparator circuit is added to compare the two derived signals, then the fault detection accuracy is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent monitors parameter changes (deviations) between the two derived signals by comparing their values against a predefined tolerance range. This approach enables accurate fault detection through parameter comparison rather than requiring complex analysis circuits.
Data Source
AI summary
A switching circuit for checking an analog input circuit of an A/D converter is shown. The switching circuit comprises the analog circuit and a comparator circuit. The analog input circuit is configured to generate a first derived signal S1 and a second derived signal S2 from an analog input signal SE of the analog input circuit. The first derived signal S1 and the second derived signal S2 are input signals for the comparator circuit, but only the first derived signal S1 is an input signal for the A/D converter. The comparator circuit is configured to check whether a deviation of the derived signals S1, S2 from each other lies within a tolerance range TOL and to output an output signal SA depending on the check, which may be further evaluated.