Flash Controller Sudden Power Off Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sudden power off events caused by unstable power supplies can lead to erroneous data programming in flash memory devices, as NAND flash devices are not random access and require specific command sequences for data access, making it difficult to prevent programming errors during power instability.
Innovation Solution
A method and apparatus that include a power detection module to repeatedly check voltage thresholds, issue program commands to a flash module, and perform supervision procedures to ensure data integrity during power fluctuations, and reconstruct flash-to-host mapping tables during sudden power off recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage threshold detection and supervision procedures are implemented, then data programming reliability is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary voltage threshold detection before initiating data programming operations. The power detection module continuously monitors voltage levels and issues warnings before unstable power conditions cause programming errors, preventing erroneous data from being written to the flash module.
Solution Approach 2:
The system implements a feedback mechanism where the power detection module continuously monitors voltage levels and provides real-time feedback to the control logic. When voltage drops below predetermined thresholds, the system receives feedback signals and executes supervision procedures including canceling programming commands and preventing data recovery operations.
2Reliability
If voltage monitoring and command cancellation procedures are implemented, then data integrity is improved, but processing time increases
Solution Approach 1:
The system performs preliminary voltage threshold detection before initiating data programming operations. The power detection module continuously monitors voltage levels and issues warnings before unstable power conditions cause programming errors, preventing erroneous data from being written to the flash module.
Solution Approach 2:
When voltage instability is detected, the system immediately skips the normal programming completion sequence and rushes to cancel the programming command. The supervision procedure detects voltage drops and quickly interrupts the programming operation, preventing time from being wasted on completing erroneous programming operations.
3Reliability
If supervision procedures are performed during programming, then programming error prevention is improved, but energy consumption increases
Solution Approach 1:
The power detection module performs periodic voltage threshold checks during the programming operation rather than continuous monitoring. The supervision procedure samples voltage at predetermined intervals and cancels the programming command only when voltage drops below the threshold, reducing energy consumption while maintaining programming error prevention.
Data Source
AI summary
The invention relates to a method, and an apparatus for accessing to data in response to a power-supply event. The method, performed by a flash controller, includes steps for: reading a plurality of physical pages of data in a current block from a flash module during a sudden power off recovery procedure; determining whether a power-supply event has occurred according to an error correction result corresponding to read physical pages; reconstructing a first flash-to-host mapping (F2H) table to include physical-to-logical mapping (P2L) information from the 0th page to a page before a last valid page in the current block when the power-supply event has occurred; and programming the reconstructed first F2H table into a location of the flash module.