Patents by Inventor Kazuyasu Fujishima

Kazuyasu Fujishima 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).

  • Patent number: 6859403
    Abstract: Drains of first and second transistors are connected to a low level line of an internal circuitry such as a sense amplifier related to determination of a potential in a memory cell. The first transistor has its gate diode-connected to a sense drive line and its source grounded. The second transistor receives at its gate an internally generated signal, and its source is grounded. In the standby state, the potential of the sense drive line is set higher than low level of said word lines by the threshold voltage Vthn of the first transistor and used as dummy GND potential Vss?, and in the active state, the second transistor is rendered conductive so as to prevent floating of the sense drive line from the dummy GND potential Vss?.
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: February 22, 2005
    Assignee: Renesas Technology Corp.
    Inventors: Hideto Hidaka, Mikio Asakura, Kazuyasu Fujishima, Tsukasa Ooishi, Kazutami Arimoto, Shigeki Tomishima, Masaki Tsukude
  • Publication number: 20040184332
    Abstract: Drains of first and second transistors are connected to a low level line of an internal circuitry such as a sense amplifier related to determination of a potential in a memory cell. The first transistor has its gate diode-connected to a sense drive line and its source grounded. The second transistor receives at its gate an internally generated signal, and its source is grounded. In the standby state, the potential of the sense drive line is set higher than low level of said word lines by the threshold voltage Vthn of the first transistor and used as dummy GND potential Vss′, and in the active state, the second transistor is rendered conductive so as to prevent floating of the sense drive line from the dummy GND potential Vss′.
    Type: Application
    Filed: April 2, 2004
    Publication date: September 23, 2004
    Applicant: RENESAS TECHNOLOGY CORP.
    Inventors: Hideto Hidaka, Mikio Asakura, Kazuyasu Fujishima, Tsukasa Ooishi, Kazutami Arimoto, Shigeki Tomishima, Masaki Tsukude
  • Publication number: 20020149973
    Abstract: Drains of first and second transistors are connected to a low level line of an internal circuitry such as a sense amplifier related to determination of a potential in a memory cell. The first transistor has its gate diode-connected to a sense drive line and its source grounded. The second transistor receives at its gate an internally generated signal, and its source is grounded. In the standby state, the potential of the sense drive line is set higher than low level of said word lines by the threshold voltage Vthn of the first transistor and used as dummy GND potential Vss′, and in the active state, the second transistor is rendered conductive so as to prevent floating of the sense drive line from the dummy GND potential Vss′.
    Type: Application
    Filed: June 7, 2002
    Publication date: October 17, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Hideto Hidaka, Mikio Asakura, Kazuyasu Fujishima, Tsukasa Ooishi, Kazutami Arimoto, Shigeki Tomishima, Masaki Tsukude
  • Patent number: 6414883
    Abstract: Drains of first and second transistors are connected to a low level line of an internal circuitry such as a sense amplifier related to determination of a potential in a memory cell. The first transistor has its gate diode-connected to a sense drive line and its source grounded. The second transistor receives at its gate an internally generated signal, and its source is grounded. In the standby state, the potential of the sense drive line is set higher than low level of said word lines by the threshold voltage Vthn of the first transistor and used as dummy GND potential Vss′, and in the active state, the second transistor is rendered conductive so as to prevent floating of the sense drive line from the dummy GND potential Vss′.
    Type: Grant
    Filed: May 21, 2001
    Date of Patent: July 2, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideto Hidaka, Mikio Asakura, Kazuyasu Fujishima, Tsukasa Ooishi, Kazutami Arimoto, Shigeki Tomishima, Masaki Tsukude
  • Patent number: 6404056
    Abstract: On transistors P1, P2, N1 and N2 constituting an NAND gate, a interconnection pattern W of metal having high melting point and aluminum interconnection patterns Al1 and Al2 are stacked. A local line LL for connecting transistors P1, P2, N1 and N2 to each other is formed by the interconnection pattern W of metal having high melting point, signal lines SL and SL′ for signal input/output between the NAND gate and the outside are formed by aluminum interconnection pattern Al1, and power supply lines VL and VL′ for applying power supply potentials Vcc and Vss to the NAND gate are formed by the aluminum interconnection pattern Al2. As compared with the prior art in which the local line LL is formed by the aluminum interconnection pattern Al1, the degree of freedom in layout can be improved and the layout area can be reduced.
    Type: Grant
    Filed: May 18, 1999
    Date of Patent: June 11, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigehiro Kuge, Kazutami Arimoto, Masaki Tsukude, Kazuyasu Fujishima
  • Patent number: 6404691
    Abstract: A semiconductor memory device comprises a DRAM memory cell array comprising a plurality of dynamic type memory cells arranged in a plurality of rows and columns, and an SRAM memory cell array comprising static type memory cells arranged in a plurality of rows and columns. The DRAM memory cell array is divided into a plurality of blocks each comprising a plurality of columns. The SRAM memory cell array is divided into a plurality of blocks each comprising a plurality of columns, corresponding to the plurality of blocks in the DRAM memory cell array. The SRAM memory cell array is used as a cache memory. At the time of cache hit, data is accessed to the SRAM memory cell array. At the time of cache miss, data is accessed to the DRAM memory cell array. On this occasion, data corresponding to one row in each of the blocks in the DRAM memory cell array is transferred to one row in the corresponding block in the SRAM memory cell array.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: June 11, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kazuyasu Fujishima, Yoshio Matsuda, Mikio Asakura
  • Publication number: 20010024383
    Abstract: Drains of first and second transistors are connected to a low level line of an internal circuitry such as a sense amplifier related to determination of a potential in a memory cell. The first transistor has its gate diode-connected to a sense drive line and its source grounded. The second transistor receives at its gate an internally generated signal, and its source is grounded. In the standby state, the potential of the sense drive line is set higher than low level of said word lines by the threshold voltage Vthn of the first transistor and used as dummy GND potential Vss′, and in the active state, the second transistor is rendered conductive so as to prevent floating of the sense drive line from the dummy GND potential Vss′.
    Type: Application
    Filed: May 21, 2001
    Publication date: September 27, 2001
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideto Hidaka, Mikio Asakura, Kazuyasu Fujishima, Tsukasa Ooishi, Kazutami Arimoto, Shigeki Tomishima, Masaki Tsukude
  • Patent number: 6272055
    Abstract: Drains of first and second transistors are connected to a low level line of an internal circuitry such as a sense amplifier related to determination of a potential in a memory cell. The first transistor has its gate diode-connected to a sense drive line and its source grounded. The second transistor receives at its gate an internally generated signal, and its source is grounded. In the standby state, the potential of the sense drive line is set higher than low level of said word lines by the threshold voltage Vthn of the first transistor and used as dummy GND potential Vss′, and in the active state, the second transistor is rendered conductive so as to prevent floating of the sense drive line from the dummy GND potential Vss′.
    Type: Grant
    Filed: October 9, 1998
    Date of Patent: August 7, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideto Hidaka, Mikio Asakura, Kazuyasu Fujishima, Tsukasa Ooishi, Kazutami Arimoto, Shigeki Tomishima, Masaki Tsukude
  • Patent number: 6214664
    Abstract: In a semiconductor device and a method of manufacturing the same, an isolating and insulating film is provided at an end neighboring to a second impurity region with a groove extended to a semiconductor substrate. This removes a crystal defect existed at the end of the isolating and insulating film, and thus prevents leak of a current at this portion from a storage node. Consequently, provision of the groove at the edge portion of the isolating oxide film neighboring to the impurity region removes a crystal defect at this region, and thus eliminates a possibility of leak of a current.
    Type: Grant
    Filed: November 18, 1999
    Date of Patent: April 10, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hiroshi Kimura, Tadashi Nishimura, Takahiro Tsuruda, Kazutami Arimoto, Tadato Yamagata, Kazuyasu Fujishima
  • Patent number: 6075732
    Abstract: A semiconductor memory device comprises two memory cell arrays (1a, 1b) in which a block divisional operation is performed. Two spare rows (2a, 2b) are provided corresponding to the two memory cell arrays (1a, 1b). Spare row decoders (5a, 5b) are provided for selecting the spare rows (2a, 2b), respectively. One spare row decoder selecting signal generation circuit (18) used in common by the spare row decoders (5a, 5b) is provided. The spare row decoder selecting signal generation circuit (18) can be previously set so as to generate a spare row decoder selecting signal (SRE) when a defective row exists in either of the memory cell arrays (1a, 1b) and the defective row is selected by row decoder groups (4a, 4b). Each of the spare row decoders (5a, 5b) is activated in response to the spare row decoder selecting signal (SRE) and a block control signal.
    Type: Grant
    Filed: June 17, 1999
    Date of Patent: June 13, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tsukasa Ooishi, Yoshio Matsuda, Kazutami Arimoto, Masaki Tsukude, Kazuyasu Fujishima
  • Patent number: 6069379
    Abstract: In a semiconductor device and a method of manufacturing the same, an isolating and insulating film is provided at an end neighboring to a second impurity region with a groove extended to a semiconductor substrate. This removes a crystal defect existed at the end of the isolating and insulating film, and thus prevents leak of a current at this portion from a storage node. Consequently, provision of the groove at the edge portion of the isolating oxide film neighboring to the impurity region removes a crystal defect at this region, and thus eliminates a possibility of leak of a current.
    Type: Grant
    Filed: November 6, 1997
    Date of Patent: May 30, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hiroshi Kimura, Tadashi Nishimura, Takahiro Tsuruda, Kazutami Arimoto, Tadato Yamagata, Kazuyasu Fujishima
  • Patent number: 5982678
    Abstract: A semiconductor memory device comprises two memory cell arrays (1a, 1b) in which a block divisional operation is performed. Two spare rows (2a, 2b) are provided corresponding to the two memory cell arrays (1a, 1b). Spare row decoders (5a, 5b) are provided for selecting the spare rows (2a, 2b), respectively. One spare row decoder selecting signal generation circuit (18) used in common by the spare row decoders (5a, 5b) is provided. The spare row decoder selecting signal generation circuit (18) can be previously set so as to generate a spare row decoder selecting signal (SRE) when a defective row exists in either of the memory cell arrays (1a, 1b) and the defective row is selected by row decoder groups (4a, 4b). Each of the spare row decoders (5a, 5b) is activated in response to the spare row decoder selecting signal (SRE) and a block control signal.
    Type: Grant
    Filed: June 26, 1997
    Date of Patent: November 9, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tsukasa Ooishi, Yoshio Matsuda, Kazutami Arimoto, Masaki Tsukude, Kazuyasu Fujishima
  • Patent number: 5969420
    Abstract: On transistors P1, P2, N1 and N2 constituting an NAND gate, interconnection pattern W of metal having high melting point and aluminum interconnection patterns Al1 and Al2 are stacked. A local line LL for connecting transistors P1, P2, N1 and N2 to each other is formed by the interconnection pattern W of metal having high melting point, signal lines SL and SL' for signal input/output between the NAND gate and the outside are formed by aluminum interconnection pattern Al1, and power supply lines VL and VL' for applying power supply potentials Vcc and Vss to the NAND gate are formed by the aluminum interconnection pattern Al2. As compared with the prior art in which the local line LL is formed by the aluminum interconnection pattern Al1, the degree of freedom in layout can be improved and the layout area can be reduced.
    Type: Grant
    Filed: June 24, 1997
    Date of Patent: October 19, 1999
    Assignee: Mitsubushi Denki Kabushiki Kaisha
    Inventors: Shigehiro Kuge, Kazutami Arimoto, Masaki Tsukude, Kazuyasu Fujishima
  • Patent number: 5943273
    Abstract: Drains of first and second transistors are connected to a low level line of an internal circuitry such as a sense amplifier related to determination of a potential in a memory cell. The first transistor has its gate diode-connected to a sense drive line and its source grounded. The second transistor receives at its gate an internally generated signal, and its source is grounded. In the standby state, the potential of the sense drive line is set higher than low level of said word lines by the threshold voltage Vthn of the first transistor and used as dummy GND potential Vss', and in the active state, the second transistor is rendered conductive so as to prevent floating of the sense drive line from the dummy GND potential Vss'.
    Type: Grant
    Filed: July 23, 1997
    Date of Patent: August 24, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideto Hidaka, Mikio Asakura, Kazuyasu Fujishima, Tsukasa Ooishi, Kazutami Arimoto, Shigeki Tomishima, Masaki Tsukude
  • Patent number: 5894440
    Abstract: Each of divided bit line pairs is selectively connected to a sub-input/output line pair through transfer gates. A register is connected to the sub-input/output line pair. Data is transferred through the sub-input/output line pair between the register and a selected bit line pair. A sense amplifier is connected to each of the bit line pairs. Sense amplifiers are independently driven by separate sense amplifier activating signals. Therefore, even if data is transferred to the selected bit line pair from the register, fluctuations in potential on the bit line pair caused in such a case does not affect a sense amplifier activating signal connected to a non-selected bit line pair. As a result, data stored in the non-selected memory cell is prevented from being destroyed.
    Type: Grant
    Filed: January 31, 1994
    Date of Patent: April 13, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masaki Tsukude, Kazutami Arimoto, Kazuyasu Fujishima, Yoshio Matsuda, Tsukasa Ooishi
  • Patent number: 5687123
    Abstract: Drains of first and second transistors are connected to a low level line of an internal circuitry such as a sense amplifier related to determination of a potential in a memory cell. The first transistor has its gate diode-connected to a sense drive line and its source grounded. The second transistor receives at its gate an internally generated signal, and its source is grounded. In the standby state, the potential of the sense drive line is set higher than low level of said word lines by the threshold voltage Vthn of the first transistor and used as dummy GND potential Vss', and in the active state, the second transistor is rendered conductive so as to prevent floating of the sense drive line from the dummy GND potential Vss'.
    Type: Grant
    Filed: September 30, 1994
    Date of Patent: November 11, 1997
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideto Hidaka, Mikio Asakura, Kazuyasu Fujishima, Tsukasa Ooishi, Kazutami Arimoto, Shigeki Tomishima, Masaki Tsukude
  • Patent number: 5682343
    Abstract: Main bit lines MBL and ZMBL are disposed at opposite sides of a sense amplifier SA. Main bit lines MBL and ZMBL each are provided for paired sub-bit lines SBL1 and SBL2 (or SBL3 and SBL4). Sub-bit line pair SBL1 and SBL2 is connected to main bit line MBL via a block select switch T1. Sub-bit line pair SBL3 and SBL4 is connected to main bit line ZMBL via a block select switch T2. Since one main bit line is provided for two sub-bit lines, a pitch of the main bit lines is twice as large as a pitch of the sub-bit lines, so that conditions on the pitch of main bit lines are remarkably eased, which facilitates layout of elements.
    Type: Grant
    Filed: June 17, 1996
    Date of Patent: October 28, 1997
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigeki Tomishima, Masaki Tsukude, Mikio Asakura, Kazuyasu Fujishima
  • Patent number: 5588130
    Abstract: A semiconductor memory device comprises a DRAM memory cell array comprising a plurality of dynamic type memory cells arranged in a plurality of rows and columns, and an SRAM memory cell array comprising static type memory cells arranged in a plurality of rows and columns. The DRAM memory cell array is divided into a plurality of blocks each comprising a plurality of columns. The SRAM memory cell array is divided into a plurality of blocks each comprising a plurality of columns, corresponding to the plurality of blocks in the DRAM memory cell array. The SRAM memory cell array is used as a cache memory. At the time of cache hit, data is accessed to the SRAM memory cell array. At the time of cache miss, data is accessed to the DRAM memory cell array. On this occasion, data corresponding to one row in each of the blocks in the DRAM memory cell array is transferred to one row in the corresponding block in the SRAM memory cell array.
    Type: Grant
    Filed: August 1, 1994
    Date of Patent: December 24, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kazuyasu Fujishima, Yoshio Matsuda, Mikio Asakura
  • Patent number: RE36027
    Abstract: In a dynamic RAM of a CSL system, a memory array is divided into a plurality of memory array portions, and bit line pairs provided in the respective memory array portions are connected to their corresponding I/O line pairs simultaneously in response to a CSL output. In such an RAM, only the I/O line pair of a memory array portion to be accessed is precharged to the level of V.sub.CC -V.sub.th, while the I/O line pair of a memory array portion not to be accessed is precharged to the level of 1/2.multidot.V.sub.CC which is the same level as the bit line pairs. This makes it possible to achieve a faster data reading operation and also prevent unnecessary currents from flowing between the bit line pairs and the I/O line pair in the unaccessed memory array portion.
    Type: Grant
    Filed: June 13, 1996
    Date of Patent: January 5, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kazutami Arimoto, Kazuyasu Fujishima, Hideto Hidaka, Masaki Tsukude, Tsukasa Ohishi
  • Patent number: RE36089
    Abstract: Column address A0-A11 is once predecoded by a first predecoder PD1, a second predecoder PD2, and a CDE buffer CDB and then applied to a column decoder CD. Column decoder CD selectively drives one of a plurality of column selecting lines CSL on the basis of the applied predecoded signals. This causes corresponding bit lines in respective memory cell arrays MCA1-MCA4 to be simultaneously selected. Column decoder CD includes a plurality of column drivers corresponding to the plurality of column selecting lines, and the column drivers are divided into a plurality of groups. The predecoded signals applied from second predecoder PD2 and CDE buffer CDB to column decoder CD are generated independently for respective groups, and signal lines for them are also distributed to respective groups. This causes the length of wiring of each predecoded signal line to be shortened.
    Type: Grant
    Filed: May 23, 1996
    Date of Patent: February 9, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tsukasa Ooishi, Kazutami Arimoto, Hideto Hidaka, Masanori Hayashikoshi, Shinji Kawai, Mikio Asakura, Masaki Tsukude, Katsuhiro Suma, Shigeki Tomishima, Kazuyasu Fujishima