Flash Memory Controller Tag-Based Error Correction

The patent applies preliminary action by storing a tag value in advance that indicates the storage type (SLC or MLC) before power failure or reset can occur. This tag value is retrieved first during system initialization to determine which voltage reference to use, ensuring the correct recognition criterion is applied without requiring the actual read/write mapping to be intact. This preliminary retrieval of the tag resolves the contradiction by enabling fast data recognition while preventing operation errors through advance preparation of the storage type information.

The patent introduces an intermediary tag value that mediates between the two different storage types (SLC and MLC). Instead of directly implementing complex switching logic for multiple voltage references, the tag value serves as an intermediary indicator that simplifies the system's decision-making process. The controller reads this tag first and then selects the appropriate voltage reference (Vref_SLC or Vref_MLC) based on the tag value, thereby maintaining high recognition accuracy while reducing system complexity through this intermediary mechanism.

The patent applies segmentation by separating the storage type identification function from the actual data storage function. The tag value is stored separately in a dedicated location (such as a specific block or page) to indicate whether the FLASH memory is operating in SLC or MLC mode. This segmentation allows the system to quickly retrieve the storage type information without reading the actual data, thereby reducing error susceptibility during power failure events while maintaining the high storage capacity benefits of MLC operation.