Flash Memory Read Voltage Compensation for Temperature Errors
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Solution Overview
Problem
Non-volatile data storage devices, such as flash SSDs, face increased bit error rates due to temporary temperature effects, leading to premature marking of storage elements as unusable, reducing capacity and useful life.
Innovation Solution
Implementing a temperature compensation technique that adjusts memory access parameters, specifically read threshold voltages, during post-write read operations to verify data integrity in multi-level cell memory, thereby reducing erroneous identification of storage elements as faulty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple bits are stored per flash memory cell to increase storage density, then storage density is improved, but bit error rate increases
Solution Approach 1:
The patent adjusts read threshold voltages based on temperature conditions to compensate for temperature-induced errors in MLC flash memory. By dynamically changing the voltage parameter during read operations, the system maintains higher reliability across varying temperatures while preserving the high storage density achieved through multi-bit-per-cell storage.
2Reliability
If post-write read operations are performed to verify data integrity, then data reliability is improved, but storage elements may be prematurely marked as unusable due to temperature effects
Solution Approach 1:
The patent applies preliminary temperature compensation by adjusting read threshold voltages before performing post-write read verification. This preemptive adjustment prevents temperature-induced errors from causing false failure detections, thereby avoiding premature marking of storage elements as unusable and preserving usable storage capacity.
Solution Approach 2:
The system dynamically modifies read voltage parameters based on detected temperature conditions during post-write verification. This parameter adjustment ensures accurate data verification while preventing false positives that would otherwise reduce the pool of usable storage elements.
3Device complexity
If standard read operations are used without temperature compensation, then device complexity is reduced, but measurement precision of data verification deteriorates
Solution Approach 1:
The patent implements temperature-based parameter adjustment where read threshold voltages are modified according to detected temperature conditions. This approach maintains relatively simple device architecture while significantly improving data read accuracy and verification precision through dynamic voltage parameter changes.
Data Source
AI summary
A device is disclosed that includes a data write engine configured to store data into a block of a memory. The device also includes a post-write read engine configured to adjust a read voltage responsive to an output of the temperature sensor and to read stored data from the block based on the adjusted read voltage to verify integrity of the data. The device also includes a block manager configured to initiate a corrective operation responsive to an error characteristic of the data read from the block.