Memory Controller Read Reclaim via Dummy Region Voltage Detection
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Solution Overview
Problem
The existing memory systems face challenges in maintaining stability and efficiency due to performance deterioration and read disturbances, particularly in portable electronic devices where repeated read operations lead to data loss and reduced utility efficiency.
Innovation Solution
A memory system with a controller that applies pass voltages to a dummy region to detect parameters and perform read reclaim operations, copying data from affected memory blocks to minimize read disturbances and maintain system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If repeated read operations are performed on memory blocks, then data access speed is improved, but read disturbances occur leading to data loss and performance deterioration
Solution Approach 1:
The controller performs read reclaim operations proactively by detecting read disturbance parameters (voltage offsets, operation counts) before actual data loss occurs. Pass voltages are applied to dummy regions in advance to detect degradation trends, and data is copied from affected memory blocks to healthy blocks before the read disturbances cause permanent damage, thus maintaining both speed and reliability
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors read disturbance parameters by applying pass voltages to dummy regions and detecting voltage offsets. Based on this feedback information about memory block health status and operation counts, the controller dynamically decides when to perform read reclaim operations, adjusting its behavior according to the actual state of the memory device to prevent data loss while maintaining efficient access
2Reliability
If read reclaim operations are performed frequently to prevent read disturbances, then data stability is improved, but memory device efficiency and productivity deteriorate
Solution Approach 1:
The controller uses parameter-based decision making for read reclaim operations. It detects specific parameters including voltage offsets from pass voltage applications, command operation counts, and read disturbance levels. Instead of frequent fixed-schedule reclaim operations, the system performs reclaim operations selectively based on whether detected parameters exceed predetermined thresholds, thus maintaining data stability while avoiding unnecessary operations that would reduce productivity
Solution Approach 2:
The system applies partial read reclaim actions only to specific memory blocks that show signs of degradation, rather than performing full reclaim operations on the entire memory device. By targeting only affected blocks based on detected parameters, the system maintains data stability in critical areas while minimizing the overall impact on memory device efficiency and productivity
3Measurement precision
If pass voltages are applied to detect parameters in dummy regions, then read disturbance detection precision is improved, but device complexity increases
Solution Approach 1:
The system uses dummy regions as intermediary structures for detecting read disturbances. These dummy regions, located in dummy word lines or dummy pages of memory blocks, serve as test areas where pass voltages can be applied without affecting actual data storage. The controller detects voltage offsets in these dummy regions to infer read disturbance levels in data regions, achieving high detection precision while keeping the main data storage areas intact and the overall system design relatively simple
Data Source
AI summary
A memory system includes: a memory device that includes a plurality of memory blocks each of which includes a plurality of pages that store data; and a controller suitable for performing command operations corresponding to a plurality of commands received from a host on the plurality of memory blocks, applying pass voltages to a dummy region of the memory device when the command operations are performed, detecting first parameters for the plurality of memory blocks based on the applied pass voltages, and copying and storing data stored in first memory blocks in second memory blocks among the plurality of memory blocks based on the first parameters.