Memory Timing Test Circuit With XOR Gates and Oscillator Edge Counting
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Solution Overview
Problem
Existing technologies face challenges in accurately measuring timing specifications such as read speed, access time, setup time, and hold time of memory devices, which are crucial for ensuring normal operations and identifying defects.
Innovation Solution
A test device and method utilizing an XOR gate, oscillator, and output circuit to determine access time by counting rising edges of an oscillation signal, and chain circuits with different delay times to measure unit delay and setup/hold times, enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used, then the test device structure is simple, but the measurement precision of timing specifications is insufficient
Solution Approach 1:
The patent introduces an oscillator as an intermediary component that generates oscillation signals serving as a reference for timing measurements. The oscillator works conjunction with XOR gates and counters to enable precise measurement of access time, setup time, and hold time specifications, thereby resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent replaces conventional mechanical or simple electrical measurement methods with a signal-based measurement system using oscillation signals, XOR logic operations, and electronic counters. This substitution enables more precise timing measurements while maintaining a relatively compact device structure through efficient use of logic circuits
2Measurement precision
If timing measurement is performed without proper reference signals, then the device complexity is low, but the measurement precision deteriorates
Solution Approach 1:
The patent applies preliminary action by generating oscillation signals in advance that serve as reference signals for timing measurements. These pre-generated oscillation signals enable accurate measurement of access time, setup time, and hold time without requiring complex real-time reference generation during the measurement process
Solution Approach 2:
The oscillator acts as an intermediary reference signal generator that provides stable timing references for measurement. By introducing this intermediary component, the system achieves high measurement precision for access time and other timing parameters without requiring overly complex measurement circuits
Data Source
AI summary
A test device for a memory device includes a first exclusive OR (XOR) gate configured to output a first operation signal by performing an XOR operation between a clock signal and an output signal output from the memory device, an oscillator configured to output an oscillation signal, and an output circuit configured to determine a period of the oscillation signal. The output circuit may be configured to count a number of rising edges of the oscillation signal while the first operation signal is maintained at a high level, and determine an access time of the memory device based on the counted number of the rising edges, and a period of the oscillation signal.