Patents by Inventor Takeshi Sakata
Takeshi Sakata 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: 7505296Abstract: The range-specified IP addresses are effectively stored to reduce the number of necessary entries thereby the memory capacity of TCAM is improved. The representative means of the present invention is that: the storage information (entry) and the input information (comparison information or search key) are the common block code such that any bit must be the logical value ‘1’; Match-lines are hierarchically structured and memory cells are arranged at the intersecting points of a plurality of sub-match lines and a plurality of search lines; Further the sub-match lines are connected to main-match lines through the sub-match detectors, respectively and main-match detectors are arranged on the main-match lines.Type: GrantFiled: October 23, 2007Date of Patent: March 17, 2009Assignees: Hitachi, Ltd., Elpida Memory, Inc.Inventors: Satoru Hanzawa, Takeshi Sakata, Kazuhiko Kajigaya
-
Publication number: 20090059702Abstract: A direct sense amplifier of the present invention incorporates and isolates: an MOS transistor serving as a differential pair and having a gate connected to a bit line; and an MOS transistor controlled by a column select line wired between RLIO lines in a bit-line direction, and further connects a source of the MOS transistor serving as the differential pair to a common source line wired in the word-line direction. Since the direct sense amplifier only in a select map is activated by the column select line and the common source line during an read operation, power consumption is significantly reduced during the read operation. Also, since a parasitic capacitance of the MOS transistor serving as the differential pair is separated from the local IO line, a load capacity of the local IO line is reduced and the read operation is speeded up. In addition, during the read operation, a data pattern dependency of the load capacity of the local IO line is reduced and a post-manufacture test is easily made.Type: ApplicationFiled: October 8, 2008Publication date: March 5, 2009Inventors: Tomonori Sekiguchi, Shinichi Miyatake, Takeshi Sakata, Riichiro Takemura, Hiromasa Noda, Kazuhiko Kajigaya
-
Patent number: 7492644Abstract: There is achieved a high-integrated and high-speed nonvolatile memory which can stabilize an operation of a phase-change memory for a short operation cycle time. A latch is provided in a write driver. A change to a high-resistance state of a phase-change element is performed per column cycle by a write-enable signal, and a change to a low-resistance state thereof is performed after a pre-charge command is inputted and concurrently with deactivation of a pre-charge signal. Thereby, a write time to a memory cell in which phase-change resistance is changed to a low-resistance state, and a period from a write operation for changing the phase-change resistance to a high-resistance state to a read operation to the above memory cell can be lengthened without extending the column cycle time, so that the stable write operation is achieved.Type: GrantFiled: August 2, 2007Date of Patent: February 17, 2009Assignees: Hitachi, Ltd., Elpida Memory, Inc.Inventors: Riichiro Takemura, Takeshi Sakata, Norikatsu Takaura, Kazuhiko Kajigaya
-
Publication number: 20090027984Abstract: The present invention provides a sense circuit for DRAM memory cell to cover the events that a sense time becomes remarkably longer when a power source voltage is lowered, a sense time under the low voltage condition becomes shorter when temperature rises and a sense time changes to a large extent for fluctuation of processes. The present invention provides the following typical effects. A switch means is provided between the bit line BL and local bit line LBL connected to the memory cells for isolation and coupling of these bit lines. The bit line BL is precharged to the voltage of VDL/2, while the local bit line LBL is precharged to the voltage of VDL. The VDL is the maximum amplitude voltage of the bit line BL. A sense amplifier SA comprises a first circuit including a differential MOS pair having the gate connected to the bit line BL and a second circuit connected to the local bit line LBL for full amplitude amplification and for holding the data.Type: ApplicationFiled: September 30, 2008Publication date: January 29, 2009Inventors: HIROYUKI MIZUNO, Takeshi Sakata, Nobuhiro OODAIRA, Takao Watanabe, Yusuke Kanno
-
Publication number: 20080309369Abstract: A semiconductor device including first and second power lines, and first and second circuit blocks coupled between the power lines. A first switching element is inserted between the first circuit block and at least one of the power lines and a second switching element is inserted between the second circuit block and at least one of the power lines. The first switching element is rendered conductive to allow the first circuit block to receive the power voltage through the first and second power lines while the second switching element is rendered nonconductive to prevent the second circuit block from receiving the power voltage through the first and second power lines, so that a leakage current flowing through the second circuit is suppressed.Type: ApplicationFiled: June 5, 2008Publication date: December 18, 2008Inventors: Takeshi SAKATA, Kiyoo ITOH, Masashi HORIGUCHI
-
Patent number: 7447091Abstract: A direct sense amplifier of the present invention incorporates and isolates: an MOS transistor serving as a differential pair and having a gate connected to a bit line; and an MOS transistor controlled by a column select line wired between RLIO lines in a bit-line direction, and further connects a source of the MOS transistor serving as the differential pair to a common source line wired in the word-line direction. Since the direct sense amplifier only in a select map is activated by the column select line and the common source line during an read operation, power consumption is significantly reduced during the read operation. Also, since a parasitic capacitance of the MOS transistor serving as the differential pair is separated from the local IO line, a load capacity of the local IO line is reduced and the read operation is speeded up. In addition, during the read operation, a data pattern dependency of the load capacity of the local IO line is reduced and a post-manufacture test is easily made.Type: GrantFiled: February 15, 2007Date of Patent: November 4, 2008Assignees: Hitachi, Ltd., Elpida Memory, Inc., Hitachi ULSI Systems Co., Ltd.Inventors: Tomonori Sekiguchi, Shinichi Miyatake, Takeshi Sakata, Riichiro Takemura, Hiromasa Noda, Kazuhiko Kajigaya
-
Patent number: 7436722Abstract: The present invention provides a sense circuit for DRAM memory cell to cover the events that a sense time becomes remarkably longer when a power source voltage is lowered, a sense time under the low voltage condition becomes shorter when temperature rises and a sense time changes to a large extent for fluctuation of processes. The present invention provides the following typical effects. A switch means is provided between the bit line BL and local bit line LBL connected to the memory cells for isolation and coupling of these bit lines The bit line BL is precharged to the voltage of VDL/2, while the local bit line LBL is precharged to the voltage of VDL. The VDL is the maximum amplitude voltage of the bit line BL. A sense amplifier SA comprises a first circuit including a differential MOS pair having the gate connected to the bit line BL and a second circuit connected to the local bit line LBL for full amplitude amplification and for holding the data.Type: GrantFiled: June 12, 2007Date of Patent: October 14, 2008Assignees: Renesas Technology Corp., Hitachi ULSI Systems Co., Ltd.Inventors: Hiroyuki Mizuno, Takeshi Sakata, Nobuhiro Oodaira, Takao Watanabe, Yusuke Kanno
-
Patent number: 7397878Abstract: The present invention provides a data communication method and a data communication device capable of performing high-speed data communication by using a parallel link and higher-speed data communication by reducing a timing skew. A data communication method includes: a step of encoding data of N bits (N being 2 or larger) to transmission data of M bits (M being 3 or larger) on a transmission side; a step of generating a transmission signal in which transition takes place in at least one level of any of the transmission data synchronously with a transmission clock and transmitting the transmission signal to a transmission line on the transmission side; a step of recognizing transition in the signal of M bits received via the transmission line and detecting the reception data of M bits synchronized with the transmission clock on a reception side; and a step of decoding the reception data of M bits to the data of N bits.Type: GrantFiled: March 4, 2003Date of Patent: July 8, 2008Assignee: Renesas Technology Corp.Inventors: Yuichi Okuda, Takeshi Sakata, Takashi Sato
-
Patent number: 7397879Abstract: The present invention provides a data communication method and a data communication device capable of performing high-speed data communication by using a parallel link and higher-speed data communication by reducing a timing skew. A data communication method includes: a step of encoding data of N bits (N being 2 or larger) to transmission data of M bits (M being 3 or larger) on a transmission side; a step of generating a transmission signal in which transition takes place in at least one level of any of the transmission data synchronously with a transmission clock and transmitting the transmission signal to a transmission line on the transmission side; a step of recognizing transition in the signal of M bits received via the transmission line and detecting the reception data of M bits synchronized with the transmission clock on a reception side; and a step of decoding the reception data of M bits to the data of N bits.Type: GrantFiled: March 4, 2003Date of Patent: July 8, 2008Assignee: Renesas Technology Corp.Inventors: Yuichi Okuda, Takeshi Sakata, Takashi Sato
-
Patent number: 7388400Abstract: A semiconductor integrated circuit with an operating voltage having an absolute value is 2.5 V or below includes circuit blocks to which operation voltage is supplied by first and second power lines and a first switching element for each circuit block. Each circuit block includes a first MOS transistor in which a leakage current flows even under a condition that a gate voltage is equal to a source voltage. Each of the first switching elements controls the leakage current flowing through a corresponding first MOS transistor of each circuit block. Also, while one of the first switching elements is controlled to reduce the leakage current flowing through the circuit block relating to one of the first switching elements, another one of the first switching elements is controlled to allow current to flow through the circuit block relating to another one of the first switching elements.Type: GrantFiled: June 27, 2007Date of Patent: June 17, 2008Assignee: Elpida Memory, Inc.Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
-
Publication number: 20080121860Abstract: A semiconductor memory cell and forming method thereof utilizes a vertical select transistor to eliminate the problem of a large cell surface area in memory cells of the related art utilizing phase changes. A memory cell with a smaller surface area than the DRAM device of the related art is achieved by the present invention. Besides low power consumption during read operation, the invention also provides phase change memory having low power consumption even during write operation. Phase change memory also has stable read-out operation.Type: ApplicationFiled: January 16, 2008Publication date: May 29, 2008Inventors: Hideyuki Matsuoka, Kiyoo Itoh, Motoyasu Terao, Satoru Hanzawa, Takeshi Sakata
-
Patent number: 7366001Abstract: The range-specified IP addresses are effectively stored to reduce the number of necessary entries thereby the memory capacity of TCAM is improved. The representative means of the present invention is that: the storage information (entry) and the input information (comparison information or search key) are the common block code such that any bit must be the logical value ‘1’; Match-lines are hierarchically structured and memory cells are arranged at the intersecting points of a plurality of sub-match lines and a plurality of search lines; Further the sub-match lines are connected to main-match lines through the sub-match detectors, respectively and main-match detectors are arranged on the main-match lines.Type: GrantFiled: December 23, 2004Date of Patent: April 29, 2008Assignees: Hitachi, Ltd., Elpida Memory, Inc.Inventors: Satoru Hanzawa, Takeshi Sakata, Kazuhiko Kajigaya
-
Publication number: 20080089137Abstract: A dummy cell includes a plurality of first memory cells MC for storing “1” or “0”, arranged at points of intersection between a plurality of word lines WR0 to WR7 and a plurality of first data lines D0 to D7, a plurality of first dummy cells MCH for storing “1” or “0”, arranged at points of intersection between the word lines WR0 to WR7 and a first dummy data line, and a plurality of second dummy cells MCL for storing “0”, arranged at points of intersection between the word lines WR0 to WR7 and a second dummy data line DD1.Type: ApplicationFiled: October 16, 2007Publication date: April 17, 2008Inventors: Satoru HANZAWA, Takeshi Sakata
-
Patent number: 7359471Abstract: The present invention provides a data communication method and a data communication device capable of performing high-speed data communication by using a parallel link and higher-speed data communication by reducing a timing skew. A data communication method includes: a step of encoding data of N bits (N being 2 or larger) to transmission data of M bits (M being 3 or larger) on a transmission side; a step of generating a transmission signal in which transition takes place in at least one level of any of the transmission data synchronously with a transmission clock and transmitting the transmission signal to a transmission line on the transmission side; a step of recognizing transition in the signal of M bits received via the transmission line and detecting the reception data of M bits synchronized with the transmission clock on a reception side; and a step of decoding the reception data of M bits to the data of N bits.Type: GrantFiled: March 4, 2003Date of Patent: April 15, 2008Assignee: Renesas Technology Corp.Inventors: Yuichi Okuda, Takeshi Sakata, Takashi Sato
-
Publication number: 20080072085Abstract: A semiconductor integrated circuit device is composed of logic gates each provided with at least two MOS transistors. The logic gates are connected to a first potential point and a second potential point. The semiconductor integrated circuit device includes a current control device connected between the logic gate and the first potential point and/or between the logic gate and the second potential point for controlling a value of a current flowing in the logic gate depending on an operating state of the logic gate. The circuit can be used in devices that cycle in operation between high and low power consumption modes, such as microprocessors that have both an operation mode and a low power back-up or sleep mode used for power reduction.Type: ApplicationFiled: October 31, 2007Publication date: March 20, 2008Inventors: Masashi Horiguchi, Kunio Uchiyama, Kiyoo Itoh, Takeshi Sakata, Masakazu Aoki, Takayuki Kawahara
-
Patent number: 7345938Abstract: A sense amplifier capable of performing high-speed data sense operation with lower power consumption using a minuscule signal from a memory cell even in a case where a memory array voltage is reduced. A plurality of drive switches for over-driving are distributively arranged in a sense amplifier area, and a plurality of drive switches for restore operation are concentratively disposed at one end of a row of the sense amplifiers. A potential for over-driving is supplied using a meshed power line circuit. Through the use of the drive switches for over-driving, initial sense operation can be performed on data line pairs with a voltage having an amplitude larger than a data-line amplitude, allowing implementation of high-speed sense operation. The distributed arrangement of the drive switched for over-driving makes it possible to dispersively supply current in sense operation, thereby reducing a difference in sense voltage with respect to far and near positions of the sense amplifiers.Type: GrantFiled: May 9, 2007Date of Patent: March 18, 2008Assignee: Renesas Technology Corp.Inventors: Riichiro Takemura, Kiyoo Itoh, Tomonori Sekiguchi, Takeshi Sakata, Katsutaka Kimura
-
Publication number: 20080062736Abstract: The object of the invention is to avoid an unselected data line being driven in a memory array composed of memory cells each of which uses a storage element depending upon variable resistance and a selection transistor when the selection transistors in all memory cells on a selected wordline conduct. To achieve the object, a source line parallel to a data line is provided, a precharge circuit for equipotentially driving both and a circuit for selectively driving the source line are arranged. Owing to this configuration, a current path is created in only a cell selected by a row decoder and a column decoder and a read-out signal can be generated. Therefore, a lower-power, lower-noise and more highly integrated nonvolatile memory such as a phase change memory can be realized, compared with a conventional type.Type: ApplicationFiled: October 25, 2007Publication date: March 13, 2008Inventors: Satoru Hanzawa, Kiyoo Itoh, Hideyuki Matsuoka, Motoyasu Terao, Takeshi Sakata
-
Publication number: 20080061298Abstract: A semiconductor memory device includes a plurality of memory cells, each including, a source region formed of a semiconductor material, a drain region formed of the semiconductor material, and a first region formed of the semiconductor material and located between the source region and the drain region. First and second insulator films sandwich the first region and a first gate electrode is connected to the first region through the first insulator film. In this arrangement, the first region is adapted to accumulate charges corresponding to stored information.Type: ApplicationFiled: October 31, 2007Publication date: March 13, 2008Inventors: Kazuo YANO, Tomoyuki Ishii, Takashi Hashimoto, Koichi Seki, Masakazu Aoki, Takeshi Sakata, Yoshinobu Nakagome, Kan Takeuchi
-
Patent number: 7341892Abstract: A semiconductor memory cell and forming method thereof utilizes a vertical select transistor to eliminate the problem of a large cell surface area in memory cells of the related art utilizing phase changes. A memory cell with a smaller surface area than the DRAM device of the related art is achieved by the present invention. Besides low power consumption during read operation, the invention also provides phase change memory having low power consumption even during write operation. Phase change memory also has stable read-out operation.Type: GrantFiled: March 7, 2006Date of Patent: March 11, 2008Assignee: Hitachi, Ltd.Inventors: Hideyuki Matsuoka, Kiyoo Itoh, Motoyasu Terao, Satoru Hanzawa, Takeshi Sakata
-
Publication number: 20080049481Abstract: The range-specified IP addresses are effectively stored to reduce the number of necessary entries thereby the memory capacity of TCAM is improved. The representative means of the present invention is that: the storage information (entry) and the input information (comparison information or search key) are the common block code such that any bit must be the logical value ‘1’; Match-lines are hierarchically structured and memory cells are arranged at the intersecting points of a plurality of sub-match lines and a plurality of search lines; Further the sub-match lines are connected to main-match lines through the sub-match detectors, respectively and main-match detectors are arranged on the main-match lines.Type: ApplicationFiled: October 23, 2007Publication date: February 28, 2008Inventors: Satoru Hanzawa, Takeshi Sakata, Kazuhiko Kajgaya