A/D Conversion Circuit for Sample-Hold Retention Testing
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Solution Overview
Problem
Current A/D conversion circuit tests do not adequately evaluate the retention characteristics of sample hold circuits and the overall A/D conversion operation, including previous circuits, which is crucial for high accuracy motor control in automotive systems.
Innovation Solution
An A/D conversion circuit with multiple transmission paths, switches, and hold circuits that allow for selective output of signal or reference voltages, enabling testing of A/D conversion operations including previous circuits, and a test method involving sequential voltage retention characteristics measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional A/D conversion circuit tests are used, then the A/D conversion operation can be tested, but the retention characteristics of sample hold circuits and previous circuits cannot be adequately evaluated
Solution Approach 1:
The circuit is divided into multiple transmission paths (first transmission path for signal voltage, second transmission path for reference voltage) that can be independently controlled and tested. This segmentation allows separate testing of different circuit components including the sample hold circuit and A/D conversion unit, enabling comprehensive evaluation without increasing overall system complexity
Solution Approach 2:
The switch circuit is designed to serve multiple functions: it can selectively connect different transmission paths, enable or disable the sample hold circuit, and provide test signals. This multi-functionality allows a single circuit structure to perform both normal operation and comprehensive testing of retention characteristics
2Measurement precision
If multiple transmission paths with switches and hold circuits are added for comprehensive testing, then retention characteristics can be evaluated, but the circuit complexity increases
Solution Approach 1:
The test function is merged with the normal operation function within the same circuit structure. The first and second transmission paths are integrated into the existing A/D conversion circuit, allowing comprehensive testing of retention characteristics without adding separate dedicated test equipment or significantly increasing circuit complexity
Data Source
AI summary
An A/D conversion circuit includes a plurality of transmission paths that transmit signal voltages and reference voltages, and an A/D conversion unit that A/D converts voltages output from the transmission paths. Each of the plurality of transmission paths includes a first switch that selectively outputs one of the signal voltage and the reference voltage, an S/H circuit that holds output voltage from the first switch, and a second switch that selectively outputs one of the output voltage from the first switch and output voltage from the S/H circuit.