Memory CSP Synchronization Using Rolling CAPAR Windows
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Solution Overview
Problem
Semiconductor memory devices face challenges in accurately determining the command start point (CSP) due to errors in command address parity checking, leading to malfunctions when transitioning from a sleep state, especially with high-frequency clock signals, as existing methods fail to detect errors in the CSP command.
Innovation Solution
Implementing a memory device with a control logic circuit, clock circuit, and CA parity circuit that performs a command address parity (CAPAR) checking operation, utilizing rolling windows delayed by one clock cycle to synchronize the CSP command with a clock signal, ensuring accurate detection of errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the memory device uses high-frequency clock signals to increase data transfer rate, then productivity is improved, but measurement precision of command start point deteriorates
Solution Approach 1:
The command address parity checking is divided into multiple sequential operations corresponding to rolling windows. Each window checks a specific time segment (4 WCK clock cycles) for CSP command presence and validity, allowing precise detection at high frequencies by breaking down the continuous signal into discrete checkable segments.
Solution Approach 2:
The memory device performs preliminary parity checking operations on incoming command addresses before executing memory operations. By pre-validating the CSP command through multiple parity check operations, the system ensures accurate command start point detection even at high clock frequencies where timing errors are more likely.
2Reliability
If the memory device performs CA parity checking to improve signal integrity, then reliability is improved, but device complexity increases
Solution Approach 1:
The CA parity circuit is designed to perform multiple functions: detecting CSP command presence, validating command address integrity, and identifying timing alignment. This multi-functional approach improves reliability through comprehensive checking while avoiding the need for separate dedicated circuits for each function, thus controlling device complexity.
Solution Approach 2:
The parity checking system uses the existing command address bus and internal logic resources to perform self-validation. The CA[4:0] signals are checked against expected parity patterns without requiring external validation circuits, allowing the memory device to self-verify command integrity and reduce overall system complexity.
Data Source
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.