Abstract: A device includes a memory including a first set of storage elements and a second set of storage elements. The device further includes circuitry coupled to the memory and configured to perform a data folding operation to fold second data from the second set of storage elements with respect to first data stored at the first set of storage elements. Each storage element of the first set of storage elements is designated to store at least three bits per storage element, and each storage element of the second set of storage elements is designated to store at least two bits per storage element.

Abstract: A multi-plane non-volatile memory die includes circuits that receive and apply different parameters to different planes while accessing planes in parallel so that different erase blocks are accessed using individualized parameters. Programming parameters, and read parameters can be modified on a block-by-block basis with modification based on the number of write-erase cycles or other factors.

Abstract: A non-volatile memory system that has two or more sub-blocks in a block performs a check before accessing memory cells to see if the condition of a sub-block that is not being accessed could affect the memory cells being accessed. If such a sub-block is found then parameters used to access the cells may be modified according to a predetermined scheme.

Abstract: In a multi-level cell (MLC) nonvolatile memory array, data is assigned sequentially to the lower and upper page of a word line, then both lower and upper pages are programmed together before programming a subsequent word line. Word lines of multiple planes are programmed together using latches to hold data until all data is transferred. Tail-ends of data of write commands are stored separately.

Abstract: In a nonvolatile memory array in which a NAND string includes a back gate that has a charge storage element, the threshold voltage of the back gate is monitored, and if the threshold voltage deviates from a desired threshold voltage range, charge is added to, or removed from the charge storage element to return the threshold voltage to the desired threshold voltage range.

Abstract: Data that is stored in a higher error rate format in a nonvolatile memory is backed up in a lower error rate format. Data to be stored may be transferred once to on-chip data latches where it is maintained while it is programmed in both the high error rate format and the low error rate format without being resent to the nonvolatile memory.

Abstract: A NAND flash memory chip includes a first partition that has smaller memory cells, with smaller charge storage elements, and a second partition that has larger memory cells, with larger charge storage elements, in the same memory array. Data is selected for storage in the first or second partition according to characteristics, or expected characteristics, of the data.

Abstract: When data from a portion of a three dimensional NAND memory array is determined to be uncorrectable by Error Correction Code (ECC), a determination is made as to whether data is uncorrectable by ECC throughout some unit that is larger than the portion. If modified read conditions provide ECC correctable data, the modified read conditions are recorded for subsequent reads of the larger unit.

Abstract: A multi-plane non-volatile memory die includes circuits that receive and apply different parameters to different planes while accessing planes in parallel so that different erase blocks are accessed using individualized parameters. Programming parameters, and read parameters can be modified on a block-by-block basis with modification based on the number of write-erase cycles or other factors.

Abstract: Portions of data stored in a three dimensional memory array are selected based on their locations for calculation of redundancy data. Locations are selected so that no two portions in a set of portions for a given calculation are likely to become uncorrectable at the same time. Selected portions may be separated by at least one word line and separated by at least one string in a block.

Abstract: In a nonvolatile NAND memory array, a NAND block may be falsely determined to be in an erased condition because of the effect of unwritten cells prior to the erase operation. Such cells may be programmed with dummy data prior to erase, or parameters used for a verify operation may be modified to compensate for such cells. Read operations may be similarly modified to compensate for unwritten cells.

Abstract: In a nonvolatile memory array, such as a three-dimensional array of charge-storage memory cells, data is scrubbed according to a scheme which weights particular data that is exposed to potentially damaging voltages. Data that may cause damage to other data is moved to a location where such potential damage is reduced.

Abstract: In a nonvolatile memory array, such as a three-dimensional array of charge-storage memory cells, data is randomized so that data of different strings along the same bit line are randomized using different keys and portions of data along neighboring word lines are randomized using different keys. Keys may be rotated so that data of a particular word line is randomized according to different keys in different strings.

Abstract: Data that is stored in a higher error rate format in a nonvolatile memory is backed up in a lower error rate format. Data to be stored may be transferred once to on-chip data latches where it is maintained while it is programmed in both the high error rate format and the low error rate format without being resent to the nonvolatile memory. High error rate format may be MLC format and programming in the high error rate format may program both lower page and upper page data together in a full sequence programming scheme that is suitable for handling high data volume.

Abstract: Lower page data that may be endangered by programming upper page data in the same memory cells is protected during upper programming using protective upper page programming schemes. High overall programming speeds are maintained by selectively using protective upper programming schemes only where endangered data is committed and may not be recoverable from another location.

Abstract: A method of determining whether a page of NAND flash memory cells is in an erased condition includes applying a first set of read conditions to identify a first number of cells having threshold voltages above a discrimination voltage under the first set of read conditions, if the first number of cells is less than a first predetermined number, applying a second set of read conditions that is different from the first set of read conditions to identify a second number of cells having threshold voltages above the discrimination voltage under the second set of read conditions, and if the second number of cells exceeds a second predetermined number, marking the page of flash memory cells as partially programmed.

Abstract: A Multi Level Cell (MLC) nonvolatile memory is tested and, if it fails to meet an MLC specification, is reconfigured for operation as an SLC memory by assigning two of the MLC memory cell states as SLC states in a first SLC mode, according to predefined sets of criteria. Subsequently, different MLC memory cell states are assigned as SLC states in a second SLC mode.

Abstract: In a nonvolatile memory that stores data in two or more different data storage formats, such as binary and MLC, a separation scheme is used to distribute blocks containing data in one data storage format (e.g. binary) so that they are separated by at least some minimum number of blocks using another data storage format (e.g. MLC).

Abstract: In a nonvolatile memory array in which a select transistor includes a charge storage element, the threshold voltage of the select transistor is monitored, and if the threshold voltage deviates from a desired threshold voltage range, charge is added to, or removed from the charge storage element to return the threshold voltage to the desired threshold voltage range.

Abstract: When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.