Memory Controller ISPP Recovery for Sudden Power-Off
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Solution Overview
Problem
Existing storage devices face challenges in efficiently recovering from sudden power-offs during program operations, leading to data loss and operational inefficiencies due to the limitations of traditional programming methods.
Innovation Solution
The implementation of an Incremental Step Pulse Program (ISPP) method by a memory controller to perform a dummy program operation on selected pages after a power-off, using a higher program start voltage and step voltage, and reducing the number of program loops compared to normal operations, thereby minimizing data loss and recovery time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional programming methods are used for dummy program operation after sudden power-off, then data integrity can be maintained, but recovery time and operational efficiency deteriorate due to requiring full program loops
Solution Approach 1:
The patent applies partial action by performing only the necessary portion of the program operation after sudden power-off. Instead of executing complete program loops, the system performs a reduced set of program loops that are sufficient to maintain data integrity while significantly reducing recovery time. This selective execution of partial program operations resolves the contradiction between maintaining reliability and reducing time loss.
Solution Approach 2:
The patent changes operational parameters by adjusting the number of program loops based on the power-off detection state. When sudden power-off is detected, the system modifies the program loop count parameter from the normal full loops to a reduced number of loops, enabling faster recovery while maintaining sufficient data integrity. This parameter adaptation resolves the trade-off between reliability and recovery time.
2Productivity
If Incremental Step Pulse Program method with higher voltages and fewer loops is used for dummy program operation, then productivity and recovery speed improve, but manufacturing precision and program accuracy may worsen
Solution Approach 1:
The system performs partial program operations with sufficient precision for the recovery context. By executing only the necessary portion of program loops with higher voltages, the system achieves adequate programming accuracy for post-power-off recovery without requiring the full precision of normal programming operations. This partial action approach maintains sufficient accuracy while dramatically improving recovery speed.
Solution Approach 2:
The patent dynamically adjusts programming parameters based on operational context. During normal operations, full precision programming is used, but after sudden power-off detection, the system transitions to a dynamic recovery mode with higher voltages and fewer loops. This dynamic parameter adjustment resolves the contradiction by adapting precision requirements to the specific operational state, achieving high productivity during recovery while maintaining adequate accuracy.
Data Source
AI summary
A storage device may include a memory device and a memory controller. The memory device may include a memory block including a plurality of pages. When a sudden power off is detected in which power supplied to the memory device is abnormally interrupted during a normal program operation on one page among the plurality of pages, the memory controller may control the memory device to perform a dummy program operation on a selected page among the plurality of pages after the sudden power-off. The memory controller may control the memory device to perform the normal program operation and the dummy program operation by using an Incremental Step Pulse Program (ISPP) method. The memory controller may control the memory device to perform the dummy program operation in a smaller number of program loops as compared with the normal program operation.