A/D Converter Clock-Loss Detection Through Output Data Comparison
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Solution Overview
Problem
Existing fault detection apparatuses for A/D converters that operate with an externally supplied clock signal cannot detect failures caused by a loss of the clock signal, particularly in converters with a single input channel, and do not account for synchronization issues resulting from open-circuit conditions in the clock signal lead.
Innovation Solution
A fault detection apparatus that performs periodic A/D conversion operations synchronized with the external clock signal, acquiring and comparing sets of output digital data to detect variations, which indicate a failure when the data remains unchanged across multiple clock signal periods, thereby diagnosing loss of the external clock signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the A/D converter operates with an externally supplied clock signal, then the A/D conversion speed and synchronization are improved, but the system becomes vulnerable to clock signal loss which cannot be detected by existing fault detection apparatus
Solution Approach 1:
The fault detection apparatus performs preliminary actions by acquiring output digital data at multiple predetermined timings within each clock period before the next conversion starts. This allows the system to establish a baseline of expected data consistency and detect any deviations caused by clock signal loss, enabling proactive fault detection rather than waiting for conversion errors to manifest
Solution Approach 2:
The apparatus implements a feedback mechanism by continuously comparing output digital data acquired at different timings within each clock period. When data inconsistency is detected across multiple acquisitions, the system generates a fault indication, creating a closed-loop feedback system that monitors the health of the clock signal connection and provides real-time diagnostic information
2Measurement precision
If the fault detection method uses multiple input channels to detect A/D converter failure, then the detection capability is improved, but the method cannot be applied to single-channel A/D converters which are commonly used in radar systems
Solution Approach 1:
The invention transitions from detecting faults across the spatial dimension (multiple input channels) to detecting faults across the temporal dimension (multiple acquisition timings within a single clock period). By acquiring data at different times rather than different channels, the system maintains high detection precision while being fully compatible with single-channel A/D converters used in radar applications
3Device complexity
If the A/D converter performs conversion once per clock period, then the device complexity is reduced, but the system cannot detect when conversions occur at random timings due to clock signal loss
Solution Approach 1:
The fault detection apparatus employs periodic action by acquiring output digital data at multiple predetermined timings within each clock period. This periodic sampling approach allows the system to detect whether conversions are occurring at the expected regular intervals or at random timings, enabling detection of clock signal loss without increasing the overall conversion operation frequency or device complexity
Data Source
AI summary
An A/D converter performs successive A/D conversion operations that are synchronized with respective periods of an externally supplied clock signal. A set of output digital data produced from the A/D converter, following each A/D conversion, is acquired a plurality of times in succession within an interval that extends to the start of the next A/D conversion operation. If identical sets of data are not obtained in the successive acquisitions, then it is determined that there is failure of the A/D converter due to loss of the external clock signal.