摘要:
A group of non-volatile memory cells are programmed in a programming pass by a series of incremental programming pulses where each pulse is followed by a program-verify and possibly program-inhibition step. Performance is improved during the programming pass by delayed starting and prematurely terminating the various verify levels that demarcate the multiple memory states. This amounts to skipping the verifying and inhibiting steps of the fastest and slowest programming (fringe) cells of the group. A reference pulse is established when the fastest cells have all been program-verified relative to a first verify level. The starting of what verify level at what pulse will then be delayed relative to the reference pulse. Verifying stops for a given verify level when only a predetermined number of cells remain unverified relative to that given level. Any errors arising from over- or under-programming of the fringe cells are corrected by an error correction code.
摘要:
A group of non-volatile memory cells are programmed in a programming pass by a series of incremental programming pulses where each pulse is followed by a program-verify and possibly program-inhibition step. Performance is improved during the programming pass by delayed starting and prematurely terminating the various verify levels that demarcate the multiple memory states. This amounts to skipping the verifying and inhibiting steps of the fastest and slowest programming (fringe) cells of the group. A reference pulse is established when the fastest cells have all been program-verified relative to a first verify level. The starting of what verify level at what pulse will then be delayed relative to the reference pulse. Verifying stops for a given verify level when only a predetermined number of cells remain unverified relative to that given level. Any errors arising from over- or under-programming of the fringe cells are corrected by an error correction code.
摘要:
A group of non-volatile memory cells are programmed in a programming pass by a series of incremental programming pulses where each pulse is followed by a program-verify and possibly program-inhibition step. Performance is improved during the programming pass by delayed starting and prematurely terminating the various verify levels that demarcate the multiple memory states. This amounts to skipping the verifying and inhibiting steps of the fastest and slowest programming (fringe) cells of the group. A reference pulse is established when the fastest cells have all been program-verified relative to a first verify level. The starting of what verify level at what pulse will then be delayed relative to the reference pulse. Verifying stops for a given verify level when only a predetermined number of cells remain unverified relative to that given level. Any errors arising from over- or under-programming of the fringe cells are corrected by an error correction code.
摘要:
Easily implemented randomization within a flash memory EEPROM reduces the NAND string resistance effect, program disturbs, user read disturbs, and floating gate to floating gate coupling that result from repeated and long term storage of specific data patterns. The randomization may be code generated pseudo randomization or user driven randomization in different embodiments. User driven commands, the timing of which cannot be predicted may be used to trigger and achieve a high level of randomization. Randomly altering the encoding scheme of the data prevents repeated and long term storage of specific data patterns. Even if a user wishes to store the same information for long periods, or to repeatedly store it, it will be randomly encoded with different encoding schemes, and the data pattern will therefore be varied.
摘要:
A group of non-volatile memory cells are programmed in a programming pass by a series of incremental programming pulses where each pulse is followed by a program-verify and possibly program-inhibition step. Performance is improved during the programming pass by delayed starting and prematurely terminating the various verify levels that demarcate the multiple memory states. This amounts to skipping the verifying and inhibiting steps of the fastest and slowest programming (fringe) cells of the group. A reference pulse is established when the fastest cells have all been program-verified relative to a first verify level. The starting of what verify level at what pulse will then be delayed relative to the reference pulse. Verifying stops for a given verify level when only a predetermined number of cells remain unverified relative to that given level. Any errors arising from over- or under-programming of the fringe cells are corrected by an error correction code.
摘要:
Easily implemented randomization within a flash memory EEPROM reduces the NAND string resistance effect, program disturbs, user read disturbs, and floating gate to floating gate coupling that result from repeated and long term storage of specific data patterns. The randomization may be code generated pseudo randomization or user driven randomization in different embodiments. User driven commands, the timing of which cannot be predicted may be used to trigger and achieve a high level of randomization. Randomly altering the encoding scheme of the data prevents repeated and long term storage of specific data patterns. Even if a user wishes to store the same information for long periods, or to repeatedly store it, it will be randomly encoded with different encoding schemes, and the data pattern will therefore be varied.
摘要:
A group of non-volatile memory cells are programmed in a programming pass by a series of incremental programming pulses where each pulse is followed by a program-verify and possibly program-inhibition step. Performance is improved during the programming pass by delayed starting and prematurely terminating the various verify levels that demarcate the multiple memory states. This amounts to skipping the verifying and inhibiting steps of the fastest and slowest programming (fringe) cells of the group. A reference pulse is established when the fastest cells have all been program-verified relative to a first verify level. The starting of what verify level at what pulse will then be delayed relative to the reference pulse. Verifying stops for a given verify level when only a predetermined number of cells remain unverified relative to that given level. Any errors arising from over- or under-programming of the fringe cells are corrected by an error correction code.
摘要:
In a non-volatile memory programming scheme where the memory cells are programmed in two or more sequential programming passes, when there is insufficient host data to program at least some of the memory cells during the second pass, some of the memory cells may be programmed to the wrong threshold voltage. This can be prevented by modifying the programming scheme so that this does not occur. In one implementation, this is accomplished by choosing a code scheme, which does not cause the memory cells to be programmed to the wrong threshold voltage during the second programming pass, or by programming the memory cells in accordance with substitute data that would not cause the cells to be programmed to an erroneous state.
摘要:
A group of non-volatile memory cells are programmed in a programming pass by a series of incremental programming pulses where each pulse is followed by a program-verify and possibly program-inhibition step. Performance is improved during the programming pass by delayed starting and prematurely terminating the various verify levels that demarcate the multiple memory states. This amounts to skipping the verifying and inhibiting steps of the fastest and slowest programming (fringe) cells of the group. A reference pulse is established when the fastest cells have all been program-verified relative to a first verify level. The starting of what verify level at what pulse will then be delayed relative to the reference pulse. Verifying stops for a given verify level when only a predetermined number of cells remain unverified relative to that given level. Any errors arising from over- or under-programming of the fringe cells are corrected by an error correction code.
摘要:
Easily implemented randomization within a flash memory EEPROM reduces the NAND string resistance effect, program disturbs, user read disturbs, and floating gate to floating gate coupling that result from repeated and long term storage of specific data patterns. The randomization may be code generated pseudo randomization or user driven randomization in different embodiments. User driven commands, the timing of which cannot be predicted may be used to trigger and achieve a high level of randomization. Randomly altering the encoding scheme of the data prevents repeated and long term storage of specific data patterns. Even if a user wishes to store the same information for long periods, or to repeatedly store it, it will be randomly encoded with different encoding schemes, and the data pattern will therefore be varied.