Memory Refresh Module Reduces Voltage Shifts Without Erasure
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Solution Overview
Problem
Data retention issues in memory devices, such as flash memory, lead to degradation of multi-level cells, causing errors in data reading due to voltage shifts, which affect system performance and require frequent reprogramming, resulting in write amplification and reduced program-erase cycling capability.
Innovation Solution
A memory device with integrated processor circuitry that includes an erase module, program module, and refresh module to refresh data without erasure, and a memory controller with error correction and refresh trigger modules to determine and execute data refresh based on error detection, using a different programming scheme with fewer steps than initial programming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data is programmed into multi-level cells for higher storage capacity, then storage density is improved, but data retention deteriorates due to voltage shifts and degradation
Solution Approach 1:
The patent applies preliminary action by performing a refresh operation before data is completely degraded. The system monitors data integrity and executes a refresh programming operation to restore voltage levels before significant degradation occurs, preventing read errors and maintaining data retention in multi-level cells
Solution Approach 2:
The patent changes programming parameters by using a simplified programming scheme for refresh operations compared to initial programming. The refresh operation uses different voltage levels and fewer programming steps optimized for restoring data in multi-level cells, thereby improving data retention while maintaining storage density
2Reliability
If frequent reprogramming is performed to maintain data integrity, then data retention is improved, but write amplification increases and program-erase cycling capability decreases
Solution Approach 1:
The patent applies local quality by performing refresh operations selectively on only those data blocks or pages that show signs of degradation, rather than refreshing the entire memory. This targeted approach maintains data retention for affected regions while minimizing unnecessary write operations on already healthy data, thereby reducing write amplification and preserving program-erase cycling capability
3Speed
If a simplified programming scheme is used for refresh operations, then programming speed is improved, but programming precision may deteriorate
Solution Approach 1:
The patent applies partial action by using a simplified programming scheme that performs only the essential programming steps needed for refresh operations, omitting certain verification and optimization steps used in initial programming. This achieves sufficient precision for restoring data while significantly improving programming speed for refresh operations
Data Source
AI summary
Systems, apparatuses, and methods are provided that refresh data in a memory. Data is programmed into the memory. After which, part or all of the data may be refreshed. The refresh of the data may be different from the initial programming of the data in one or more respects. For example, the refresh of the data may include fewer steps than the programming of the data and may be performed without erasing a section of memory. Further, the refresh of the data may be triggered in one of several ways. For example, after programming the data, the data may be analyzed for errors. Based on the number of errors found, the data may be refreshed.