ADC Error Detection via AC Signal Injection
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Solution Overview
Problem
Electronic devices, such as analog-to-digital converter devices, face challenges in achieving high reliability and functional safety, particularly in automotive applications, due to the need to detect errors in connections between signal sources and converters, which current methods address by increasing complexity, chip area, and cost through redundancy.
Innovation Solution
An electronic device with an alternating current source and a detection circuit that monitors the amplitude of the voltage signal at the analog-to-digital converter input, using an alternating current digital-to-analog converter to detect errors by filtering the output and outputting an error signal if the amplitude differs from a predetermined threshold, thereby reducing the need for redundant components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant elements (like two analog-to-digital converters) are provided to achieve high reliability, then reliability is improved, but device complexity increases
Solution Approach 1:
The system uses its own operational signals (the alternating current from the AC source passing through the connection) as the test signal for error detection. The analog-to-digital converter processes both the normal sensor signal and the self-generated test signal, eliminating the need for separate test equipment or redundant converters.
Solution Approach 2:
The analog-to-digital converter serves dual purposes: it converts the normal sensor signal during operation and simultaneously converts the self-generated test signal for error detection. This multi-functionality allows the same hardware to perform both operational and diagnostic tasks.
2Reliability
If redundant elements are provided to achieve high reliability, then reliability is improved, but chip area increases
Solution Approach 1:
The error detection functionality is merged with the existing analog-to-digital converter and AC source. The detection circuit utilizes the same converter infrastructure to process test signals, combining the operational and diagnostic functions into a single integrated system rather than adding separate redundant converters.
3Reliability
If redundant elements are provided to achieve high reliability, then reliability is improved, but power consumption increases
Solution Approach 1:
The error detection operates periodically by alternating between normal operation mode and self-test mode. During normal operation, the converter processes sensor signals. During test periods, the AC source generates test signals that are processed by the same converter. This periodic switching allows error detection without continuous additional power consumption from redundant 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
This solution effectively detects connection errors, such as impedance changes and short circuits, without increasing complexity or cost, ensuring high functional safety standards like ASIL-D, while maintaining efficient operation and reducing chip area.
Implementation Method 1
an alternating current source (805) configured to supply an alternating current to the analog-to-digital-converter input (804)
Implementation Method 2
determine the amplitude of the voltage signal at the analog-to-digital-converter input (804) caused by the alternating current by filtering the output of the analog-to-digital converter
Data Source
AI summary
According to various embodiments, an electronic device is described, comprising a device input for connecting an analog signal source, an analog-to-digital converter having an analog-to-digital converter input connected to the device input, an alternating current source configured to supply an alternating current to the analog-to-digital-converter input and a detection circuit configured to store a reference for an amplitude of a voltage signal at the analog-to-digital-converter input caused by the alternating current, receive an output of the analog-to-digital converter, determine the amplitude of the voltage signal at the analog-to-digital-converter input caused by the alternating current by filtering the output of the analog-to-digital converter and output an error signal if the reference for the amplitude differs from the determined amplitude by more than a predetermined threshold.