Selective Memory Bank Refresh Control for Access During Refresh
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Solution Overview
Problem
Existing memory devices face inefficiencies in refresh operations, as all-bank refresh operations render all memory banks inaccessible, limiting accessibility during refresh cycles.
Innovation Solution
Implementing a refresh control circuit that allows for selective refresh operations on subsets of memory banks, including all-bank, same-bank, and same-bank-subset refresh modes, using mode register settings to optimize accessibility during refresh cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all-bank refresh operations are performed, then all memory banks are refreshed, but all memory banks become inaccessible during refresh cycles
Solution Approach 1:
The memory banks are divided into multiple subsets or groups, allowing refresh operations to be performed on one subset at a time while other subsets remain accessible. This segmentation enables parallel operation where refresh and access can occur simultaneously in different bank groups, resolving the contradiction between complete refresh and continuous accessibility.
Solution Approach 2:
The system dynamically switches between different refresh modes (all-bank, same-bank, same-bank-subset) based on operational requirements. This dynamic adaptation allows the memory system to optimize between refresh completeness and accessibility depending on the current workload and timing requirements.
2Reliability
If all memory banks are refreshed simultaneously, then refresh operations are completed, but system performance decreases due to downtime
Solution Approach 1:
By segmenting the refresh operation into smaller subsets of banks that can be refreshed in parallel or sequentially while others remain operational, the system maintains data integrity through complete refresh coverage while minimizing the impact on overall system performance.
Solution Approach 2:
The memory system maintains continuous useful action by ensuring that while some banks are being refreshed, other banks remain accessible for read/write operations. This continuity prevents complete system downtime and maintains productivity throughout the refresh cycle.
3Ease of operation
If selective refresh on subsets of banks is implemented, then accessibility during refresh is improved, but refresh control complexity increases
Solution Approach 1:
The refresh control is segmented into manageable units that correspond to bank groups or subsets, with each unit having simplified control logic. This modular approach to control complexity makes the system more manageable while still achieving the benefit of selective refresh.
4Reliability
If refresh operations are performed more frequently, then data retention is improved, but energy consumption increases
Solution Approach 1:
Instead of refreshing all banks at maximum frequency, the system performs partial refresh operations on only the necessary subsets of banks at the required frequency, while other banks can operate at lower refresh rates or be skipped if recently refreshed. This partial action approach maintains data retention reliability while reducing overall energy consumption.
Data Source
AI summary
Apparatuses and methods for a refresh operation performed on a memory bank from a subset of memory of memory bank groups in a high bank-count memory device. The memory banks may be divided into memory bank groups. The memory device may receive an external refresh command. The refresh command may indicate that a memory bank from each of the memory bank groups is to be refreshed (e.g., a same bank refresh operation) rather than refreshing all of the memory banks of all the memory groups (e.g., an all bank refresh operation). Responsive to the refresh command and a mode register setting further indicating that a smaller subset is to be refreshed (e.g., a same bank subset refresh operation), the refresh control circuit will refresh a memory bank from a subset of memory bank groups. As a result, the number of available memory banks during a refresh operation increases.