Memory Controller Read Conditions for Fewer NAND Read Retries
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Solution Overview
Problem
Non-volatile memory devices with multi-bit per cell storage architecture face increased read errors due to narrowed read margins and data retention issues, leading to degraded performance from excessive read retries.
Innovation Solution
A memory system that records passed read retry conditions to determine optimal combined read conditions, reducing the number of read retries by applying these conditions during operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multi-bit per cell storage architecture is used to increase storage density, then storage capacity is improved, but read errors increase due to narrowed read margins
Solution Approach 1:
The system performs preliminary read retry operations to determine optimal read conditions for different page types before actual data reading. Historical read retry results are recorded and analyzed to establish lookup tables that guide future read operations, preventing read errors before they occur by pre-configuring optimal read voltages and parameters based on page characteristics.
2Reliability
If traditional read retry operations are performed to correct read errors, then read accuracy is improved, but operational performance deteriorates due to excessive retry overhead
Solution Approach 1:
The system performs preliminary read retry operations to determine optimal read conditions for different page types before actual data reading. Historical read retry results are recorded and analyzed to establish lookup tables that guide future read operations, preventing read errors before they occur by pre-configuring optimal read voltages and parameters based on page characteristics.
Solution Approach 2:
The system creates lookup tables that store optimal read conditions derived from historical read retry operations. These lookup tables serve as simplified copies or models of complex read retry behavior, allowing the system to quickly determine appropriate read parameters without performing actual retry operations, thereby eliminating retry overhead while maintaining read accuracy.
3Reliability
If read retry operations are performed to handle data retention issues, then data reading reliability is improved, but time consumption increases due to multiple retry attempts
Solution Approach 1:
The system performs preliminary read retry operations to determine optimal read conditions for different page types before actual data reading. Historical read retry results are recorded and analyzed to establish lookup tables that guide future read operations, preventing read errors before they occur by pre-configuring optimal read voltages and parameters based on page characteristics.
Solution Approach 2:
The system creates lookup tables that store optimal read conditions derived from historical read retry operations. These lookup tables serve as simplified copies or models of complex read retry behavior, allowing the system to quickly determine appropriate read parameters without performing actual retry operations, thereby eliminating retry overhead while maintaining read accuracy.
Data Source
AI summary
In certain aspects, a memory system is disclosed. The memory system includes a non-volatile memory device configured to store data and a memory controller coupled to the non-volatile memory device. The memory controller is configured to determine one or more combined read conditions based on passed read retry conditions associated with historical read retry operations. The memory controller is further configured to control the non-volatile memory device to perform a read operation based on the one or more combined read conditions.