Page Buffer Cache Switching During Program Suspend Resume
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Solution Overview
Problem
Existing memory systems face issues with increased trigger rates due to voltage level shifts in memory cells caused by program suspend and resume operations, leading to higher bit error rates and inefficient read error handling, which adversely affect quality of service.
Innovation Solution
Implementing a memory system with a page buffer having multiple data caches and a controller that manages program operations, ensuring program data is handled appropriately during suspend and resume to prevent data overwrite, thereby maintaining accurate voltage levels and reducing trigger rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If program operations are suspended to service read operations, then quality of service is improved, but voltage level shifts occur in memory cells leading to increased trigger rates
Solution Approach 1:
The patent applies preliminary action by performing a read verify operation before resuming the program operation. This verify operation checks the voltage levels of memory cells that were programmed before suspension, allowing the system to detect and correct voltage shifts before they cause errors. The read verify acts as a preventive measure that maintains reliability while enabling program suspension for quality of service.
2Adaptability or versatility
If program suspend and resume operations are implemented, then flexibility in operation is improved, but bit error rates increase due to voltage level shifts
Solution Approach 1:
The patent implements feedback by using the read verify operation to detect voltage level shifts in memory cells after program suspension. The results of this verification are fed back to the control logic, which then adjusts subsequent program operations accordingly. This closed-loop feedback mechanism corrects voltage drift caused by suspension, maintaining low bit error rates while preserving operational flexibility.
3Productivity
If multiple suspend and resume operations occur, then read operation servicing is improved, but threshold voltage distributions become unstable
Solution Approach 1:
The patent applies preliminary action by performing read verify operations before each program resume to detect and account for voltage shifts accumulated during suspension. This preliminary verification stabilizes the threshold voltage distribution by identifying drift early, allowing the system to maintain stable voltage levels even after multiple suspend-resume cycles while continuing to service read operations efficiently.
Data Source
AI summary
One method includes suspending a program operation being performed on a group of memory cells. Prior to resuming the program operation, a program status corresponding to the program operation can be determined. The method includes, responsive to determining a first program status and prior to resuming the program operation: overwriting first program data stored in a first data cache of a page buffer with second program data stored in a second data cache of the page buffer; and resuming the program operation in the absence of the first program data. The method includes, responsive to determining a second program status and prior to resuming the program operation: preventing the first program data stored in the first data cache from being overwritten with the second program data stored in the second data cache; and resuming the program operation utilizing the first program data in the absence of the second program data.