Non-Volatile Memory Controller Adaptive Read Voltage Sampling
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Solution Overview
Problem
Conventional non-volatile memory systems face performance issues due to time-consuming error checking processes when transferring data between memory blocks, which can be inefficient and reduce system performance.
Innovation Solution
The use of offset voltage lookup tables allows a controller to efficiently verify data by dynamically sampling data based on relationships between word lines and characteristics of the memory block, such as life stage, program/erase count, and read/disturb count, enabling adaptive read level voltage and offset voltage application for accurate data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is checked at each word line prior to transfer, then error detection reliability is improved, but system performance deteriorates due to time consumption
Solution Approach 1:
The patent applies partial action by sampling only a limited amount of data at selected word lines rather than checking every word line. The controller selectively reads data from certain word lines based on sampling criteria, achieving error detection without the overhead of comprehensive checking across all word lines.
Solution Approach 2:
The patent implements preliminary action by performing error sampling checks before data transfer operations. The controller proactively identifies potential errors in the source memory block before initiating transfer, allowing preventive measures to be taken and avoiding costly post-transfer verification.
2Productivity
If limited data sampling is performed prior to transfer, then system performance is improved, but error detection reliability deteriorates
Solution Approach 1:
The patent implements feedback by using the results of sampling operations to guide subsequent data transfer decisions. The controller analyzes error patterns detected during sampling and uses this information to adjust transfer operations, potentially performing additional targeted reads or correcting errors before transfer based on the sampling feedback.
Solution Approach 2:
The patent replaces comprehensive mechanical checking of all word lines with a more efficient sampling mechanism. Instead of systematically reading every word line, the controller uses selective sampling based on metadata and error patterns, substituting a resource-intensive mechanical process with a smarter, information-driven approach.
3Reliability
If post-transfer verification is performed, then error detection reliability is improved, but system performance deteriorates due to additional read operations
Solution Approach 1:
The patent performs error detection actions preliminarily, before data transfer completes. By sampling and identifying errors in the source block before transfer, the system avoids the need for post-transfer verification reads, as errors are caught and handled in advance.
Solution Approach 2:
The patent enables skipping of post-transfer verification steps by performing adequate sampling before transfer. When sampling detects sufficient confidence in data integrity, the system can rush through the transfer operation without waiting for or performing additional verification reads after transfer completes.
Data Source
AI summary
Systems and methods for sampling data at a non-volatile memory system are disclosed. In one implementation, a controller of a non-volatile memory system that is coupled with a host device acquires a read level voltage of a first word line of a memory block of a non-volatile memory of the non-volatile memory system. The controller accesses one or more lookup tables to determine an offset voltage for a second word line of the memory block based on a program/erase count and a read/disturb count associated with the memory block; applies the read level voltage and the offset voltage to the second word line to sample data stored at the memory block; and determines whether the data sampled from the memory block contains errors.