Synchronous Semiconductor Memory Output Control Signal Generator
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Solution Overview
Problem
Synchronous semiconductor memory devices face reduced sampling margins and potential data output errors due to increased operating frequency, process, voltage, and temperature variations, and jitter, which affect the output control circuit's ability to produce valid data.
Innovation Solution
The implementation of an output control signal generator that uses delayed internal clock signals, sampling clock signals, and a data output buffer to increase the sampling margin by synchronizing data output with an external clock signal, thereby stabilizing latency control operations at high frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the operating frequency of the synchronous semiconductor memory device is increased, then the operating speed is improved, but the sampling margin of internal signals is decreased
Solution Approach 1:
The patent applies preliminary action by generating sampling clock signals in advance that are synchronized with the internal clock signal before the read information signal is sampled. This pre-synchronized timing ensures that even at high operating frequencies, the sampling margin is maintained by having the sampling clock ready at the correct phase, preventing timing errors before they occur.
2Productivity
If the operating frequency is increased, then the operating speed is improved, but data output errors may occur due to reduced sampling margin
Solution Approach 1:
The patent implements feedback by using the internal clock signal to generate sampling clock signals that are fed back into the output control signal generator. This feedback mechanism ensures that the sampling timing is continuously adjusted to match the actual internal clock frequency, maintaining accurate sampling and preventing data output errors even at high operating speeds.
3Adaptability or versatility
If process, voltage, and temperature variations are present, then manufacturing and operational flexibility are improved, but the sampling margin is decreased
Solution Approach 1:
The patent applies parameter changes by using the internal clock signal, which is generated from the external clock signal through controlled frequency division, to create sampling clock signals with adjusted timing parameters. This allows the system to adapt to process, voltage, and temperature variations by dynamically adjusting the sampling timing based on the actual internal clock frequency, thereby maintaining stable sampling margin across different operating conditions.
Data Source
AI summary
A synchronous semiconductor memory device includes an output control signal generator, which generates an output control signal corresponding to a signal obtained by delaying a read information signal in response to a delay internal clock signal obtained by dividing an internal clock signal by n, first and second sampling signals obtained by delaying the internal clock signal, a first output control clock signal obtained by dividing the internal clock signal by n, and a column address strobe (CAS) latency signal. The synchronous semiconductor memory device also includes a data output buffer, which outputs data by buffering internal data in response to the output control signal and the first output control clock signal.