Cache Block Replacement for Failed Memory Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In memory systems, frequent refresh operations for weak memory cells increase power consumption, and masking off multiple memory blocks due to a single failed cell results in wasted memory capacity.
Innovation Solution
Assigning a smaller unit cache block to replace the memory block containing the failed cell, which is locked and used as a permanent replacement, minimizing memory waste and reducing power consumption by avoiding the need for frequent refresh operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a page frame unit is masked off when a failed memory cell is detected, then the faulty memory cell is isolated, but a large portion of memory capacity is wasted
Solution Approach 1:
The patent segments the memory replacement into smaller units by introducing cache block-level replacement. Instead of masking entire page frame units, the system identifies and replaces only the specific cache blocks containing failed memory cells. This granular segmentation allows the system to isolate faults while preserving the majority of memory capacity within the same page frame unit.
Solution Approach 2:
The patent applies local quality by treating different cache blocks within a page frame unit differently based on their health status. Healthy cache blocks continue to function normally while only the affected cache blocks are replaced. This localized approach ensures that reliability is improved at the specific fault location without unnecessarily affecting other functional memory regions.
2Reliability
If frequent refresh operations are performed on weak memory cells, then data retention is improved, but power consumption increases
Solution Approach 1:
The patent extracts weak memory cells from the main memory system by replacing them with cache blocks. Once extracted, these problematic memory cells no longer require frequent refresh operations, thereby eliminating the associated power consumption. The replacement cache blocks provide the necessary data retention functionality without the high energy cost of continuous refreshing.
Solution Approach 2:
The patent uses cache blocks as disposable replacements for weak memory cells. These cache blocks serve as temporary or permanent substitutes that handle the data retention function without requiring the same maintenance (refresh operations) as the original weak memory cells. This approach trades the use of alternative storage resources for reduced operational costs in terms of power consumption.
Data Source
AI summary
A memory system includes a memory controller configured to replace a memory block including a failed memory cell with a unit cache block of a cache memory in response to detection of the failed memory cell in the memory block. The unit cache block is smaller than a minimum size of a memory cell array capable of being blocked by an operating system, and the unit cache block has substantially the same storage capacity as the memory block.