Memory Controller Refresh Command for DRAM Bank Coverage
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Solution Overview
Problem
Conventional memory systems face data loss issues due to insufficient refresh actions on DRAM memory banks within the refresh window, particularly at varying operating temperatures, as the refresh window shortens with increasing temperature, making it challenging for memory controllers to issue sufficient per-bank refresh commands within the allotted time.
Innovation Solution
A refresh control method that dynamically issues refresh commands with a memory bank number field and a memory bank count field, allowing the memory controller to selectively perform refresh operations on a subset of memory banks within the refresh window, ensuring all banks are refreshed before the window closes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refresh window is shortened due to increased operating temperature, then the refresh rate must be increased to prevent data loss, but the memory controller cannot issue sufficient per-bank refresh commands within the shortened time period
Solution Approach 1:
The refresh operation is segmented into two distinct modes: auto-refresh for bulk bank refreshing and manual-refresh for targeted bank refreshing. This segmentation allows the system to efficiently handle the time-critical refresh operations by combining automated bulk processing with selective manual intervention, ensuring all banks are refreshed within the shortened refresh window while preventing data loss
Solution Approach 2:
The refresh control method dynamically switches between auto-refresh and manual-refresh modes based on the refresh state and temperature conditions. The system adapts its refresh strategy in real-time, transitioning from automated bulk refreshing to targeted manual refreshing as needed, optimizing the refresh process for varying temperature states and refresh window durations
2Reliability
If per-bank refresh commands are issued sequentially to all memory banks, then each bank receives individual attention, but the total time required exceeds the refresh window at high temperatures
Solution Approach 1:
The system performs preliminary bulk refresh operations on multiple banks simultaneously using auto-refresh before the refresh window expires. This preliminary action ensures that the majority of banks are refreshed in advance, creating time buffer for any remaining banks that require manual-refresh, thus guaranteeing complete bank coverage while maintaining high productivity
Solution Approach 2:
The refresh process maintains continuous useful action by overlapping auto-refresh operations with manual-refresh preparation. The system continuously monitors the refresh window and dynamically transitions between refresh modes, ensuring uninterrupted refresh coverage across all banks throughout the entire refresh window period
Data Source
AI summary
A refresh control method for a memory controller of a memory system is provided. The memory controller is connected with a memory. The memory includes plural memory banks. The refresh control method includes the following steps. Firstly, a refresh state of the memory device is read, and thus a refresh window is realized. Then, a refresh command is issued to the memory device according to the refresh state. The refresh command contains a memory bank number field and a memory bank count field. The memory bank count field indicates a first count. The first count of memory banks are selected from the plural memory banks of the memory device according to the memory bank number field and the first count. Moreover, a refresh operation is performed on the first count of memory banks.