Memory Device CSP Synchronization With Phase-Divided Clocks
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Solution Overview
Problem
Semiconductor memory devices struggle to accurately synchronize command start points (CSP) with increasing clock frequencies, leading to potential malfunctions due to unrecognized errors in command signals, especially when transitioning from sleep states.
Innovation Solution
Implementing a memory device with a control logic circuit, clock circuit, and CA parity circuit that performs command address parity (CAPAR) checking operations, using phase-divided clock signals to synchronize CSP commands and detect errors through rolling windows, ensuring accurate command alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the clock frequency is increased to achieve higher data transfer rates, then productivity is improved, but the synchronization accuracy of command start points deteriorates
Solution Approach 1:
The patent introduces an intermediary synchronization mechanism that mediates between the high-frequency clock signal and the command start point detection. This intermediary system uses phase information from multiple clock cycles to accurately identify CSP positions without being directly limited by the high clock frequency, thus resolving the contradiction between high data transfer rate and synchronization accuracy.
Solution Approach 2:
The patent performs preliminary synchronization preparation by capturing and analyzing phase information from clock signals before actual command execution. This preliminary action allows the system to pre-determine the correct command start point alignment, ensuring accurate synchronization even at high clock frequencies where real-time detection would be difficult.
2Productivity
If the memory device exits sleep state and activates the clock signal, then productivity is improved, but the command start point synchronization deteriorates due to unrecognized errors
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors the synchronization status of command start points after clock activation from sleep state. The system uses the captured phase information to verify correct alignment and provides feedback for correction if synchronization errors are detected, thus maintaining reliability during state transitions.
Solution Approach 2:
The patent prepares for potential synchronization errors by implementing a cushioning mechanism that captures and stores phase reference information before command execution begins. This preparatory cushioning allows the system to recover from or prevent synchronization errors that may occur during wake-up transitions, ensuring reliable operation.
3Measurement precision
If CA bus training is performed to improve signal capture accuracy, then measurement precision is improved, but loss of time increases due to training overhead
Solution Approach 1:
The patent performs CA bus training and phase capture as a preliminary action during initialization or wake-up sequences. By completing the time-consuming training process beforehand, the system establishes accurate synchronization references that can be reused for subsequent operations, minimizing the impact of training time on overall productivity.
Solution Approach 2:
The patent designs the CA bus training mechanism to serve multiple functions: it not only captures phase information for synchronization but also validates signal integrity and establishes timing references for subsequent operations. This multi-functionality reduces the need for separate training operations, thereby reducing total time loss.
Data Source
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AI summary
Provided are a memory device and a method for command start point (CSP) synchronization. The memory device includes: a control logic circuit configured to receive command address (CA) signals and control an operation of the memory device; a clock circuit configured receive a clock signal and divide the clock signal to generate first to fourth phase clock signals that are respectively synchronized with first to fourth rising edges of the CA signals indicating a command start point (CSP) command, wherein the first to fourth rising edges of the CA signals constitute a command window; and a CA parity circuit configured to perform a command address parity (CAPAR) checking operation on the CSP command, wherein the CAPAR checking operation includes a plurality of operations respectively corresponding to rolling windows in which the command window is delayed by one clock cycle of the clock signal.