NAND Memory Read Offset Adaptation for Fewer Re-Reads
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Solution Overview
Problem
Existing memory read operations in NAND devices often require multiple re-reads due to temperature changes or memory deterioration, leading to inefficiency, increased wear, and time consumption.
Innovation Solution
Adopting a system that identifies a baseline offset for memory read operations based on successful re-reads, using it for subsequent reads, and adjusts the offset when necessary to minimize re-reads and improve initial read success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple re-reads are performed to ensure successful data retrieval, then read reliability is improved, but time consumption and wear on memory cells increase
Solution Approach 1:
The patent applies preliminary action by determining and storing an offset value before actual read operations. The offset is calculated based on temperature conditions and programmed into a register in advance, so that when a read operation occurs, the reference voltage can be immediately adjusted using the pre-determined offset without requiring multiple re-read attempts. This proactive approach eliminates the need for iterative re-reads and reduces time consumption while maintaining high read reliability.
2Reliability
If multiple re-reads are performed to ensure successful data retrieval, then read reliability is improved, but wear on memory cells increases
Solution Approach 1:
The patent determines the offset value in advance based on temperature conditions and stores it in a register before read operations occur. This preliminary determination allows the reference voltage to be correctly adjusted from the start, enabling successful data retrieval in a single read operation and eliminating the need for multiple re-reads that would otherwise increase wear on memory cells through repeated programming and erasing cycles.
3Reliability
If reference voltage is adjusted using offset values to improve read success rate, then read reliability is improved, but device complexity increases
Solution Approach 1:
The patent changes the parameter of reference voltage by adjusting it with temperature-dependent offset values. The offset is determined based on temperature conditions and stored in a register, allowing the reference voltage to be dynamically adjusted to match operating conditions. This parameter change approach improves read success rate while maintaining relatively simple device architecture by using straightforward voltage adjustment rather than complex circuit modifications.
4Productivity
If offset determination and adjustment mechanisms are implemented, then read efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary determination of offset values based on temperature conditions and stores them in registers before read operations. This approach improves read efficiency by ensuring the correct reference voltage is used from the start, eliminating the need for multiple re-read attempts. The complexity introduced is minimal, involving only offset calculation logic and register storage, which are straightforward additions compared to the significant efficiency gains achieved.
Data Source
AI summary
Methods, systems, and devices for determining offsets for memory read operations are described. In response to a threshold quantity of pages failing initial reads but being successfully read using a same reference adjustment during re-reads, the offset responsible for the adjustment may be used as a first-applied offset for subsequent re-reads or a baseline offset for subsequent initial reads. After the initial reads begin using the reference adjustment, if a threshold quantity of pages fail initial reads, the offset used for the initial read may be adjusted to be the offset used to perform the successful re-reads. If an updated offset to use a baseline is not identified, the baseline offset may be cleared so the original reference may again be used without adjustment for initial reads.