NAND Data Randomization Using LUT Inversion Seeds for Uniform Cell Wear

The patent applies inversion by flipping bits of the data pattern based on a pseudo-random sequence generated from an inversion seed. This inverts the approach of directly writing data, instead writing the inverted version of data to distribute cell state transitions uniformly across different program states, thereby resolving the contradiction between writing simplicity and reliability.

The patent changes the parameter of data pattern by using different inversion seeds for different program erase cycles. This causes the pseudo-random inversion sequence to vary, thereby changing how bits are flipped and distributing cell transitions uniformly across all program states, improving reliability while maintaining operational simplicity.

The patent performs preliminary action by generating a pseudo-random inversion sequence and determining the inversion seed before the actual data writing process. This preliminary randomization preparation ensures that when data is written, the cell state transitions are already distributed uniformly, preventing shallow erase issues and reducing fail bit counts without slowing down the writing speed.

The patent implements periodic action by using different inversion seeds for different program erase cycles. This periodic variation of the inversion seed causes the pseudo-random inversion pattern to change systematically, ensuring uniform distribution of cell state transitions across all cycles and preventing cumulative wear issues.

The patent applies self-service by using a look-up table that automatically provides the appropriate inversion seed based on the current program erase cycle count and physical address. This self-service mechanism eliminates the need for complex algorithms to determine inversion seeds, as the LUT autonomously provides the correct seed, thereby reducing process complexity while maintaining uniform cell wear distribution.

The patent introduces an intermediary element - the look-up table - that mediates between the program erase cycle parameters and the inversion seed selection. This intermediary simplifies the relationship by pre-computing and storing optimal inversion seeds, thereby reducing the complexity of real-time calculations while ensuring uniform cell state transition distribution.