Refresh Control Device for DRAM Bank Timing Margin Errors

The refresh control device is segmented into multiple latch circuits (first latch circuit, second latch circuit, etc.) corresponding to different banks. Each latch circuit independently receives and processes refresh commands and active signals, allowing separate control of refresh operations for each bank. This segmentation enables precise timing control for each bank independently, resolving the timing margin errors that arise from combined bank control while maintaining improved data retention reliability.

Latch circuits serve as intermediary elements between the command decoder and the banks. The latch circuits receive commands from the command decoder, buffer and synchronize them with active signals, and then generate word line enable signals for the respective banks. This intermediary mechanism allows precise timing adjustment and synchronization, eliminating timing margin errors while maintaining the benefits of separated active and refresh command processing.

The control device is divided into multiple identical latch circuit modules, each handling a specific bank. This modular segmentation allows the system to achieve improved data retention through separate command processing while keeping each individual latch circuit relatively simple. The repetition of standardized latch circuit blocks increases overall device complexity but in a manageable, systematic way that provides proportional benefits.

Each latch circuit is designed as a universal module that can handle both active commands and refresh commands for its associated bank. The latch circuits perform multiple functions: receiving commands from the command decoder, synchronizing with active signals, generating word line enable signals, and controlling bank operations. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in device complexity while achieving improved data retention reliability.

The latch circuits implement periodic refresh operations for each bank based on received refresh commands. Instead of continuous operation, the refresh is performed periodically at intervals determined by the refresh command timing. This periodic action allows the system to maintain improved data retention through regular refresh cycles while reducing current consumption by keeping circuits in a lower-power state between refresh periods.

Each latch circuit autonomously manages its own bank's refresh operations by internally generating the appropriate word line enable signals based on received commands and active signals. This self-service capability allows precise control of refresh timing for each bank without requiring additional control logic or coordination circuits, thereby limiting the increase in current consumption while achieving improved data retention through independent bank management.