Patents by Inventor Hiroto Nakai
Hiroto Nakai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6172911Abstract: The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines basing upon a change, after the pre-charge, of the potential at each bit line, without changing the column address. In the data rewrite operation, the rewrite operation is not effected for a memory cell with the data once properly written, by changing the data in the data register.Type: GrantFiled: April 1, 1999Date of Patent: January 9, 2001Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Masaki Momodomi, Hideo Kato, Hiroto Nakai, Yoshiyuki Tanaka, Riichiro Shirota, Seiichi Aritome, Yasuo Itoh, Yoshihisa Iwata, Hiroshi Nakamura, Hideko Odaira, Yutaka Okamoto, Masamichi Asano, Kaoru Tokushige
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Patent number: 6122193Abstract: Data latch circuits are provided corresponding to select memory cells from or into which read or program is executed. The data latch circuits are grouped by two into sets. When 2-bit data is read from or programmed into the select memory cells, one data latch circuit is selected by a select signal, and, when 1-bit data is read or programmed, the two data latch circuits in one set are selected by a select signal. Between one or two selected data latch circuits and a data input/output buffer, data is exchanged. By so doing, changeover between 2-level data and multi-level (4-level or more-level) data concerning program or read of data into or out the memory cells becomes possible.Type: GrantFiled: June 1, 1999Date of Patent: September 19, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Noboru Shibata, Tomoharu Tanaka, Hiroto Nakai, Toshio Yamamura, Susumu Fujimura
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Patent number: 6028794Abstract: A nonvolatile semiconductor memory device comprises a plurality of nonvolatile memory cells, which can be electrically programmed and erased, the plurality of nonvolatile memory cells divided into a plurality of blocks, a block erase circuit for erasing the plurality of nonvolatile memory cells contained in the plurality of blocks at the same time per block, erase operation times storage section for storing the number of erase operations of the nonvolatile memory cells to be erased at the same time by the block erase circuit per block in a number of erase operation storage region, and read time setting section for setting the read time based on the number of the erase operations stored in the number of erase operation storage region at the time of reading the storage data in the nonvolatile memory cells.Type: GrantFiled: January 15, 1998Date of Patent: February 22, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Hiroto Nakai, Kaoru Tokushige
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Patent number: 5909399Abstract: The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines basing upon a change, after the pre-charge, of the potential at each bit line, without changing the column address. In the data rewrite oepration, the rewrite operation is not effected for a memory cell with the data once properly written, by changing the data in the data register.Type: GrantFiled: June 19, 1998Date of Patent: June 1, 1999Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Masaki Momodomi, Hideo Kato, Hiroto Nakai, Yoshiyuki Tanaka, Riichiro Shirota, Seiichi Aritome, Yasuo Itoh, Yoshihisa Iwata, Hiroshi Nakamura, Hideko Odaira, Yutaka Okamoto, Masamichi Asano, Kaoru Tokushige
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Patent number: 5818791Abstract: The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines basing upon a change, after the pre-charge, of the potential at each bit line, without changing the column address. In the data rewrite operation, the rewrite operation is not effected for a memory cell with the data once properly written, by changing the data in the data register.Type: GrantFiled: March 27, 1997Date of Patent: October 6, 1998Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Masaki Momodomi, Hideo Kato, Hiroto Nakai, Yoshiyuki Tanaka, Riichiro Shirota, Seiichi Aritome, Yasuo Itoh, Yoshihisa Iwata, Hiroshi Nakamura, Hideko Odaira, Yutaka Okamoto, Masamichi Asano, Kaoru Tokushige
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Patent number: 5793696Abstract: The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines basing upon a change, after the pre-charge, of the potential at each bit line, without changing the column address. In the data rewrite oepration, the rewrite operation is not effected for a memory cell with the data once properly written, by changing the data in the data register.Type: GrantFiled: April 8, 1997Date of Patent: August 11, 1998Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Masaki Momodomi, Hideo Kato, Hiroto Nakai, Yoshiyuki Tanaka, Riichiro Shirota, Seiichi Aritome, Yasuo Itoh, Yoshihisa Iwata, Hiroshi Nakamura, Hideko Odaira, Yutaka Okamoto, Masamichi Asano, Kaoru Tokushige
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Patent number: 5724300Abstract: The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines basing upon a change, after the pre-charge, of the potential at each bit line, without changing the column address. In the data rewrite operation, the rewrite operation is not effected for a memory cell with the data once properly written, by changing the data in the data register.Type: GrantFiled: January 16, 1997Date of Patent: March 3, 1998Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Masaki Momodomi, Hideo Kato, Hiroto Nakai, Yoshiyuki Tanaka, Riichiro Shirota, Seiichi Aritome, Yasuo Itoh, Yoshihisa Iwata, Hiroshi Nakamura, Hideko Odaira, Yutaka Okamoto, Masamichi Asano, Kaoru Tokushige
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Patent number: 5682346Abstract: According to the present invention, a voltage level for boosting a writing voltage to be supplied to memory cells of a memory cell array, and writing time are optimized in consideration of writing efficiency and a distribution of threshold voltage. A boosting circuit boosts the writing voltage to be supplied to memory cells. A counter counts the number of writing times in accordance with a signal of a timer. The timer outputs the signal used to count the number of writing times at a fixed interval from a first writing time until an arbitrary writing time in counting a predetermined number of writing times by the counter and to count the number of writing times at an interval when the number of writing times is gradually increased after the arbitrary writing time in order to control supplying time of the writing voltage to the memory cells.Type: GrantFiled: March 29, 1996Date of Patent: October 28, 1997Assignee: Kabushiki Kaisha ToshibaInventors: Toshio Yamamura, Hiroto Nakai, Tomoharu Tanaka
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Patent number: 5615148Abstract: EEPROM for directly outputting addresses of those in which erasing failure occurs among a plurality of blocks to be erased for erasing by a plural block simultaneous erasing system to an outside of a chip and enabling a system side to directly identify the addresses thereof is provided with a plurality of cell blocks each having an array of nonvolatile memory cells, plural block simultaneous erasing control arrangement for performing cell data erasing from a plurality of cell blocks specified as to be erased for simultaneous data erasing and a block address outputting circuit for outputting, when existence of erase failure blocks is detected after block simultaneous erasing, addresses thereof to the outside of the chip.Type: GrantFiled: March 26, 1996Date of Patent: March 25, 1997Assignee: Kabushiki Kaisha ToshibaInventors: Toshio Yamamura, Hiroto Nakai
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Patent number: 5615165Abstract: The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines basing upon a change, after the pre-charge, of the potential at each bit line, without changing the column address. In the data rewrite operation, the rewrite operation is not effected for a memory cell with the data once properly written, by changing the data in the data register.Type: GrantFiled: December 21, 1995Date of Patent: March 25, 1997Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Masaki Momodomi, Hideo Kato, Hiroto Nakai, Yoshiyuki Tanaka, Riichiro Shirota, Seiichi Aritome, Yasuo Itoh, Yoshihisa Iwata, Hiroshi Nakamura, Hideko Odaira, Yutaka Okamoto, Masamichi Asano, Kaoru Tokushige
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Patent number: 5587948Abstract: A memory cell section is divided into a data storage area and a data management information storage area in a column direction. The number of memory cells of each of NAND strings of the data management information storage area is smaller than that of memory cells of each of NAND strings of the data storage area. Word lines are connected in common to NAND strings arranged in the column direction in the data storage area, and two of them extend to be connected in common to the NAND strings arranged in the column direction in the data management information storage area. Bit lines are connected in common to the NAND strings arranged in the row direction.Type: GrantFiled: June 14, 1995Date of Patent: December 24, 1996Assignee: Kabushiki Kaisha ToshibaInventor: Hiroto Nakai
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Patent number: 5553026Abstract: The non-volatile memory device comprises a memory cell array, a block decoder, and a decode signal reading section. The memory cell array has a plurality of cell blocks. Each of the cell blocks is composed of a plurality of memory cells arranged roughly into a matrix pattern. Each memory cell has a floating gate to or from which electrons are injected or extracted to write or erase data. The block decoder receives a block address, and outputs a decode signal to select a cell block corresponding to the block address from the cell blocks. The memory cells of the selected block are erased simultaneously. When a control signal is inputted to the block decoder, the block decoder outputs the decode signal to select all the cell blocks for erasure of the memory cells of all the cell blocks simultaneously, irrespective of the block address. The decode signal reading section outputs the decode signal to the outside.Type: GrantFiled: December 27, 1994Date of Patent: September 3, 1996Assignee: Kabushiki Kaisha ToshibaInventors: Hiroto Nakai, Tadashi Miyakawa, Shigeru Matsuda
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Patent number: 5546351Abstract: The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines basing upon a change, after the pre-charge, of the potential at each bit line, without changing the column address. In the data rewrite operation, the rewrite operation is not effected for a memory cell with the data once properly written, by changing the data in the data register.Type: GrantFiled: October 20, 1994Date of Patent: August 13, 1996Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Masaki Momodomi, Hideo Kato, Hiroto Nakai, Yoshiyuki Tanaka, Riichiro Shirota, Seiichi Aritome, Yasuo Itoh, Yoshihisa Iwata, Hiroshi Nakamura, Hideko Odaira, Yutaka Okamoto, Masamichi Asano, Kaoru Tokushige
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Patent number: 5450361Abstract: There is disclosed a semiconductor memory device comprising memory cells (M11 to Mmn) for storing binary data, and first reference cells (DM11 to DMm1) and second reference cells (DM12 to DMm2) corresponding to respective two storage states of the memory cell, to make comparisons between the storage state of the memory cell and the storage states of the both reference cells at first and second sense amplifiers (1, 2) to compare outputs from the both sense amplifiers at the third sense amplifier (3) to thereby detect storage data of the memory cell. Thus, there can be provided a high speed memory device which has a less number of memory cells and of a high integration structure, and which has a little possibility of an erroneous operation in reading.Type: GrantFiled: February 16, 1994Date of Patent: September 12, 1995Assignee: Kabushiki Kaisha ToshibaInventors: Hiroshi Iwahashi, Hiroto Nakai, Kazuhisa Kanazawa, Isao Sato
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Patent number: 5436913Abstract: A non-volatile semiconductor memory device has writing part (203, 205, 209) for writing data in a non-volatile memory cell in response to a write pulse, readout part (419) for reading out data stored in the memory cell, and verification part (207, 210; 417) for verifying to ensure that normal writing has been completed by reading data from the memory cell after each writing. The device repeats writings unless a normal writing can be confirmed by the verification part. At this time, the writing part can vary writing time and in a part of a sequence of repeating writing unless a normal writing can be confirmed, it sets writing time longer for the next writing action than that for one writing action. Since this setting is performed according to constant multiplication, constant increment, or constant multiplication of accumulated value, necessary time for obtaining normal data write can be reduced.Type: GrantFiled: June 1, 1993Date of Patent: July 25, 1995Assignee: Kabushiki Kaisha ToshibaInventors: Toshio Yamamura, Hiroto Nakai, Hideo Kato, Kaoru Tokushige, Masamichi Asano
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Patent number: 5428569Abstract: A non-volatile semiconductor memory device comprises: a plurality of memory cells for electrically rewriting data; a programming and erasing section for executing data writing programs and data erasing operation for the memory cells; a verifying section for discriminating whether a data is written in or erased from one of the memory cells properly whenever data are written to or erased from the memory cells; and an automatic control section for enabling the programming and erasing section to execute the data writing program and erasing operation again whenever the verifying section discriminates that data is not properly written to or erased from one of the memory cells, the data writing program or erasing operation being executed repeatedly by the number of times less than a user-defined maximum program execution or erasing operation number applied externally from the outside of the memory device. Further, the number of data writing and erasing operations can be outputted to the outside of the chip.Type: GrantFiled: March 29, 1993Date of Patent: June 27, 1995Assignee: Kabushiki Kaisha ToshibaInventors: Hideo Kato, Hiroto Nakai, Masamichi Asano, Kaoru Tokushige
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Patent number: 5371702Abstract: In response to a plurality of address signal input from the outside in sequence, an erase information inputting section controls an erase information holding section corresponding to the batch erase block to be erased so as to hold an erase information data. By repeating this operation in sequence, the erase information data are stored in the erase information holding sections corresponding to the plural batch erase blocks to be erased. Successively, on the basis of the erase information data stored in the erase information holding sections, block erasing sections are activated to erase all the nonvolatile memory cells of each of the corresponding blocks where the erase information data are held.Type: GrantFiled: March 5, 1993Date of Patent: December 6, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Hiroto Nakai, Hideo Kato, Kaoru Tokushige, Masamichi Asano, Kazuhisa Kanazawa, Toshio Yamamura
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Patent number: 5361227Abstract: The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines basing upon a change, after the pre-charge, of the potential at each bit line, without changing the column address. In the data rewrite operation, the rewrite operation is not effected for a memory cell with the data once properly written, by changing the data in the data register.Type: GrantFiled: December 18, 1992Date of Patent: November 1, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Masaki Momodomi, Hideo Kato, Hiroto Nakai, Yoshiyuki Tanaka, Riichiro Shirota, Seiichi Aritome, Yasuo Itoh, Yoshihisa Iwata, Hiroshi Nakamura, Hideko Odaira, Yutaka Okamoto, Masamichi Asano, Kaoru Tokushige
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Patent number: 5321655Abstract: There is disclosed a semiconductor memory device comprising memory cells (M11 to Mnn) for storing binary data, and first reference cells (DM11 to Dm1) and second reference cells (DM12 to DMm2) corresponding to respective two storage states of the memory cell, to make comparisons between the storage state of the memory cell and the storage states of the both reference cells at first and second sense amplifiers (1, 2) to compare outputs from the both sense amplifiers at the third sense amplifier (3) to thereby detect storage data of the memory cell. Thus, there can be provided a high speed memory device which has a less number of memory cells and of a high integration structure, and which has a little possibility of an erroneous operation in reading.Type: GrantFiled: August 24, 1993Date of Patent: June 14, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Hiroshi Iwahashi, Hiroto Nakai, Kazuhisa Kanazawa, Isao Sato
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Patent number: 5297029Abstract: In reading data, data is transferred to data registers starting from a data read start address to the last address at a row (page), and data at the next page is transferred to the data registers starting from a start address to the last address at that page. These operations are repeated. In writing data from an intermediate address of a page, predetermined data is written in data registers not having write data. It is possible to read data at consecutive pages from a first predetermined column address to the page last address, and to read data at consecutive pages from a second predetermined column address to the page last address. For the data structure having a first data structure and a second data structure, it is possible to continuously read a set of data having both the first and second data structures and a set of data having only the second data structure, improving the efficiency of a system using a semiconductor memory device.Type: GrantFiled: December 18, 1992Date of Patent: March 22, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Hiroto Nakai, Hideo Kato, Kaoru Tokushige, Masamichi Asano