Electrically erasable and programmable non-volatile memory system with
write-verify controller using two reference levels
    14.
    发明授权
    Electrically erasable and programmable non-volatile memory system with write-verify controller using two reference levels 失效
    具有写入验证控制器的电可擦除和可编程非易失性存储器系统,使用两个参考电平

    公开(公告)号:US5321699A

    公开(公告)日:1994-06-14

    申请号:US851286

    申请日:1992-03-12

    摘要: An EEPROM includes an array of memory cell transistors, which is divided into cell blocks each including NAND cell units of series-connected cell transistors. A sense amplifier is connected to bit lines and a comparator. A data-latch circuit is connected to the comparator, for latching a write-data supplied from a data input buffer. After desired cell transistors selected for programming in a selected block are once programmed, a write-verify operation is performed. The comparator compares the actual data read from one of the programmed cell transistors with the write-data, to verify its written state. The write-verify process checks the resulting threshold voltage for variations using first and second reference voltages defining the lower-limit and upper-limit of an allowable variation range. If the comparison results under employment of the first voltage shows that an irregularly written cell transistor remains with an insufficient threshold voltage which is so low as to fail to fall within the range, the write operation continues for the same cell transistor. If the comparison results under employment of the second voltage shows that an excess-written cell transistor remains, the block is rendered "protected" at least partially.

    摘要翻译: EEPROM包括存储单元晶体管的阵列,其被分成每个包括串联连接的单元晶体管的NAND单元单元的单元块。 读出放大器连接到位线和比较器。 数据锁存电路连接到比较器,用于锁存从数据输入缓冲器提供的写入数据。 在所选择的块中选择用于编程的所需单元晶体管被一次编程之后,执行写验证操作。 比较器将从编程单元晶体管之一读取的实际数据与写入数据进行比较,以验证其写入状态。 写验证过程使用限定允许变化范围的下限和上限的第一和第二参考电压来检查所得到的阈值电压的变化。 如果使用第一电压的比较结果表明,不规则写入的单元晶体管保持不足阈值电压,其不足以落在该范围内,对于相同的单元晶体管,写操作继续进行。 如果在使用第二电压的情况下的比较结果表明剩余写入过多的单元晶体管,则该块至少部分地被“保护”。

    Electrically erasable and programmable non-volatile memory system with
write-verify controller using two reference levels
    17.
    发明授权
    Electrically erasable and programmable non-volatile memory system with write-verify controller using two reference levels 失效
    具有写入验证控制器的电可擦除和可编程非易失性存储器系统,使用两个参考电平

    公开(公告)号:US5469444A

    公开(公告)日:1995-11-21

    申请号:US341955

    申请日:1994-11-16

    摘要: An EEPROM includes an array of memory cell transistors, which is divided into cell blocks each including NAND cell units of series-connected cell transistors. A sense amplifier is connected to bit lines and a comparator. A data-latch circuit is connected to the comparator, for latching a write-data supplied from a data input buffer. After desired cell transistors selected for programming in a selected block are once programmed, a write-verify operation is performed. The comparator compares the actual data read from one of the programmed cell transistors with the write-data, to verify its written state. The write-verify process checks the resulting threshold voltage for variations using first and second reference voltages defining the lower-limit and upper-limit of an allowable variation range. If the comparison results under employment of the first voltage shows that an irregularly written cell transistor remains with an insufficient threshold voltage which is so low as to fail to fall within the range, the write operation continues for the same cell transistor. If the comparison results under employment of the second voltage shows that an excess-written cell transistor remains, the block is rendered "protected" at least partially.

    摘要翻译: EEPROM包括存储单元晶体管的阵列,其被分成每个包括串联连接的单元晶体管的NAND单元单元的单元块。 读出放大器连接到位线和比较器。 数据锁存电路连接到比较器,用于锁存从数据输入缓冲器提供的写入数据。 在所选择的块中选择用于编程的所需单元晶体管被一次编程之后,执行写验证操作。 比较器将从编程单元晶体管之一读取的实际数据与写入数据进行比较,以验证其写入状态。 写验证过程使用限定允许变化范围的下限和上限的第一和第二参考电压来检查所得到的阈值电压的变化。 如果使用第一电压的比较结果表明,不规则写入的单元晶体管保持不足阈值电压,其不足以落在该范围内,对于相同的单元晶体管,写操作继续进行。 如果在使用第二电压的情况下的比较结果表明剩余写入过多的单元晶体管,则该块至少部分地被“保护”。