Methods for adaptively programming flash memory devices and flash memory systems incorporating same
View Patent ↗A method for programming a plurality of data sequences into a corresponding plurality of flash memory functional units using a programming process having at least one selectable programming duration-controlling parameter controlling the duration of the programming process for a given data sequence, the method comprising providing at least one indication of at least one varying situational characteristic and determining a value for said at least one selectable programming duration-controlling parameter controlling the duration of the programming process for a given data sequence, for each flash memory functional unit, depending at least partly on said indication of said varying characteristic; and, for each individual flash memory functional unit from among said plurality of flash memory functional units, programming a sequence of bits into said individual flash memory functional unit using a programming process having at least one selectable parameter, said at least one selectable parameter being set at said value determined for said individual flash memory functional unit.
1. A method for rapidly programming at least two bits per cell, in a population of pages belonging to respective erase sectors in flash memory, the population of pages defining a multiplicity of cells, the method comprising: for at least one cell, initially programming at least one first bit into the cell thereby to induce one of a first plurality of program levels in the cell, said first plurality of program levels including an erase level and at least one program level other than the erase level, skipping, while a cycle count of at least one erase sector that comprises the at least one cell have a predeterminedly low cycle count, a subsequence programming of at least one second bit into the cell of a certain program level that differs from the erase level and allowing the cell to remain in a program level of the first plurality of levels; and subsequently programming, after the cycle count of the at least one erase sectors that include the at least one cell exceeds the predeterminedly low cycle count, the at least one second bit into the cell, thereby to induce one of a second plurality of program levels in the cell if the at least one second bit is of a program level that differs from the certain program level.
2. A method according to claim 1 wherein said second plurality of program levels includes all of the program levels in said first plurality of program levels.
3. A method according to claim 1 wherein said at least one cell comprises only cells in pages belonging to erase sectors having a predeterminedly low cycle count.
4. A method according to claim 1 wherein said at least one cell comprises all cells in pages belonging to erase sectors having a predeterminedly low cycle count.
5. A system for rapidly programming at least two bits per cell, in a population of pages belonging to respective erase sectors in flash memory, the population of pages defining a multiplicity of cells, the system comprising: a bit programmer operative to initially program at least one first bit into at least one cell thereby to induce one of a first plurality of program levels in the cell, said first plurality of program levels including an erase level and at least one program level that differs from the erase level, to skip, while a cycle count of at least one erase sector that comprises the at least one cell have a predeterminedly low cycle count, a subsequence programming of at least one second bit into the cell of a certain program level that differs from the erase level and allowing the cell to remain in a program level of the first plurality of levels; and to subsequently program, after the cycle count of the at least one erase sectors that include the at least one cell exceeds the predeterminedly low cycle count, the at least one second bit into the cell, thereby to induce one of a second plurality of program levels in the cell if the at least one second bit is of a program level that differs from the certain program level.
6. A system according to claim 5 wherein said second plurality of program levels includes all of the program levels in said first plurality of program levels.
7. A system according to claim 5 wherein said at least one cell comprises only cells in pages belonging to erase sectors having a predeterminedly low cycle count.
8. A system according to claim 5 wherein said at least one cell comprises all cells in pages belonging to erase sectors having a predeterminedly low cycle count.
9. A method for rapidly programming at least two bits per cell, in a population of pages belonging to respective erase sectors in flash memory, the population of pages defining a multiplicity of cells, the method comprising: initially programming by a bit programmer at least one first bit into at least one cell thereby to induce one of a first plurality of program levels in the cell, said first plurality of program levels including an erase level and at least one program level that differs from the erase level, skipping, while a cycle count of at least one erase sector that comprises the at least one cell have a predeterminedly low cycle count, a subsequence programming of at least one second bit into the cell of a certain program level that differs from the erase level and allowing the cell to remain in a program level of the first plurality of levels; and subsequently programming, after the cycle count of the at least one erase sectors that include the at least one cell exceeds the predeterminedly low cycle count, the at least one second bit into the cell, thereby to induce one of a second plurality of program levels in the cell if the at least one second bit is of a program level that differs from the certain program level.