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).
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Patent number: 7224599Abstract: A phase change memory is provided with a write data register, an output data selector, a write address register, an address comparator and a flag register. Write data is not only written into a memory cell but also retained by the write data register until the next write cycle. If a read access occurs to that address before the next write cycle, data is read out from the register without reading the data from the memory cell array. Without elongating the cycle time, it is possible not only to use a long time to write data into a memory cell therein but also to make longer the interval between the time when a write operation is done and the time when the subsequent read operation is made from that memory cell. As a result, data can be written reliably.Type: GrantFiled: February 23, 2006Date of Patent: May 29, 2007Assignee: Hitachi, Ltd.Inventors: Takeshi Sakata, Kenichi Osada, Riichiro Takemura, Hideyuki Matsuoka
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Patent number: 7215136Abstract: Power dissipation of a semiconductor integrated circuit chip is reduced when it is operated at an operating voltage of 2.5 V or below. A switching element is provided in each circuit block within the chip. Constants of the switching element are set so that leakage current in each switching element in their off-state is smaller than the subthreshold current of MOS transistors within the corresponding circuit block. Active current is supplied to active circuit blocks, while switching elements of non-active circuit blocks are turned off. Thus, dissipation currents of non-active circuit blocks are limited to leakage current value of corresponding switching elements. Thus, the sum of dissipation currents of non-active circuit blocks is made smaller than the active current in the active circuit blocks. As a result, power dissipation in the semiconductor integrated circuit chip can be reduced even in the active state.Type: GrantFiled: February 17, 2006Date of Patent: May 8, 2007Assignee: Elpida Memory, Inc.Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
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Patent number: 7200061Abstract: 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: November 8, 2002Date of Patent: April 3, 2007Assignees: Hitachi, Ltd., Elpida Memory, Inc., Hitachi ULSI Systems Co., Ltd.Inventors: Tomonori Sekiguchi, Shinichi Miyatake, Takeshi Sakata, Riichiro Takemura, Hiromasa Noda, Kazuhiko Kajigaya
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Patent number: 7199639Abstract: A semiconductor device including a level converter (LSC) is disclosed. The level converter comprises a voltage-up circuit (LSC1) that operates on low voltage of power supply (VDD) and steps up voltage enough to drive the level converter and a level converter circuit (LSC2) that operates on high voltage of power supply (VDDQ). The voltage-up circuit is capable of constantly generating 2×VDD so that the level converter can convert a low voltage of power supply (VDD) below 1 V to VDDQ. This voltage-up circuit can be configured only with MOSFET transistors produced by thin oxide film deposition, thus enabling high-speed operation. To facilitate designing a circuit for preventing a leakage current from occurring in the level converter during sleep mode of a low-voltage-driven circuit (CB1), the level converter circuit (LSC2) includes a leak protection circuit (LPC) that exerts autonomous control for leak prevention, dispensing with external control signals.Type: GrantFiled: April 26, 2006Date of Patent: April 3, 2007Assignee: Renesas Technology Corp.Inventors: Yusuke Kanno, Hiroyuki Mizuno, Takeshi Sakata, Takao Watanabe
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Publication number: 20070070716Abstract: 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: ApplicationFiled: November 14, 2006Publication date: March 29, 2007Inventors: Riichiro Takemura, Takeshi Sakata, Norikatsu Takaura, Kazuhiko Kajigaya
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Patent number: 7196368Abstract: A capacitor consisting of a storage electrode (19), a capacitor dielectric film (20) and a plate electrode (21) is formed in a trench formed through dielectric films (6, 8, 10 and 12) stacked on a semiconductor substrate (1) and buried wiring layers (9 and 11) are formed under the capacitor. As the capacitor is formed not in the semiconductor substrate but over it, there is room in area in which the capacitor can be formed and the difficultly of forming wiring is reduced by using the wiring layers (9 and 11) for a global word line and a selector line. As the upper face of an dielectric film (32) which is in contact with the lower face of wiring (34) in a peripheral circuit area is extended into a memory cell area and is in contact with the side of the capacitor (33), step height between the peripheral circuit area and the memory cell area is remarkably reduced.Type: GrantFiled: August 10, 2004Date of Patent: March 27, 2007Assignee: Renesas Technology Corp.Inventors: Shinichiro Kimura, Toshiaki Yamanaka, Kiyoo Itoh, Takeshi Sakata, Tomonori Sekiguchi, Hideyuki Matsuoka
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Patent number: 7196953Abstract: Disclosed is a sense amplifier arrangement that achieves high-speed access and shorter cycle time when array voltage is lowered in a DRAM. In a TG clocking sense system to separate data lines between the array side and the sense amplifier side in an early stage of a sensing period, a restore amplifier RAP is added, which amplifies data lines on the array side by referring to the data in the sense amplifier, and the restore amplifier is driven by a voltage VDH higher than the array voltage VDL. As a result, high-speed sense operation of the TG clocking system is made compatible with high-speed restore operation of overdrive system, and it is possible to achieve high-speed access operation and shorter cycle time.Type: GrantFiled: June 7, 2005Date of Patent: March 27, 2007Assignee: Hitachi, Ltd.Inventors: Riichiro Takemura, Tomonori Sekiguchi, Takeshi Sakata
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Publication number: 20070057696Abstract: Power dissipation of a semiconductor integrated circuit chip is reduced when it is operated at an operating voltage of 2.5 V or below. A switching element is provided in each circuit block within the chip. Constants of the switching element are set so that leakage current in each switching element in their off-state is smaller than the subthreshold current of MOS transistors within the corresponding circuit block. Active current is supplied to active circuit blocks, while switching-elements of non-active circuit blocks are turned off. Thus, dissipation currents of non-active circuit blocks are limited to leakage current value of corresponding switching elements. Thus, the sum of dissipation currents of non-active circuit blocks is made smaller than the active current in the active circuit blocks. As a result, power dissipation in the semiconductor integrated circuit chip can be reduced even in the active state.Type: ApplicationFiled: November 15, 2006Publication date: March 15, 2007Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
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Patent number: 7189918Abstract: An Electronic Control Unit which houses electronic circuit for controlling various devices of vehicles in a sealing case is characterized in that the case has a ventilation hole to communicate an interior and an exterior of the case, the ventilation hole comprises a filter for preventing from entering contaminants from the outside, and a sectional area of the ventilation hole is gradually enlarged toward the interior of the case.Type: GrantFiled: October 29, 2004Date of Patent: March 13, 2007Assignees: NSK Ltd., NSK Steering Systems Co., Ltd.Inventor: Takeshi Sakata
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Patent number: 7184326Abstract: A DRAM adopting a single-intersection memory cell array having randomly accessible data registers accessed whenever the chip is accessed externally. When data items recorded in the data registers are simultaneously written in the memory cell array, the data items are encoded. When data items are read from the memory cell array into the data registers, the data items are decoded. The margin is enhanced because array noise derived from reading is reduced. In addition, the access time of the DRAM is also reduced.Type: GrantFiled: November 8, 2005Date of Patent: February 27, 2007Assignee: Renesas Technology Corp.Inventors: Tomonori Sekiguchi, Riichiro Takemura, Takeshi Sakata, Kazushige Ayukawa, Takayuki Kawahara
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Patent number: 7170792Abstract: A semiconductor device to output voltages at three levels to a word driver while alleviating the breakdown voltage in the MOS transistor. This invention is comprised of a breakdown-voltage reducing MOS transistor inserted in the word driver and two NMOS transistors to supply a read-out voltage to a word line. The word driver is moreover controlled by different voltage amplitudes on the main word lines and the common word lines.Type: GrantFiled: May 11, 2005Date of Patent: January 30, 2007Assignee: Hitachi, Ltd.Inventors: Satoru Hanzawa, Takeshi Sakata
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Publication number: 20070007070Abstract: An electric power steering unit includes: a controller 4 for controlling a drive of an electric motor 16; and a terminal base 4B, which is provided in the controller 4, which constitutes a signal terminal of the controller 4, wherein the terminal base 4B fastens a terminal by means of fastening with a bolt. Terminals of pieces of harness 16A to 16C extending from the electric motor 16 are fastened to output terminals 23A to 23C on the terminal base 4B by means of fastening bolts. The electric power steering unit more preferably includes: a contact resistance detection member (35, 36, 37) for detecting a contact resistance between each output terminal 23A to 23C and each terminal TN of the harness 16A to 16C; and an electric current control member (21, 22) for controlling a drive current supplied to the electric motor 16 with detection information obtained by this detection member.Type: ApplicationFiled: June 8, 2006Publication date: January 11, 2007Inventors: Takeshi Sakata, Nobuyuki Kobayashi, Hisayoshi Koiwai
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Patent number: 7154788Abstract: 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: November 24, 2004Date of Patent: December 26, 2006Assignees: Hitachi, Ltd., Elpida Memory, Inc.Inventors: Riichiro Takemura, Takeshi Sakata, Norikatsu Takaura, Kazuhiko Kajigaya
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Publication number: 20060280010Abstract: 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 word line 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: August 22, 2006Publication date: December 14, 2006Inventors: Satoru Hanzawa, Kiyoo Itoh, Hideyuki Matsuoka, Motoyasu Terao, Takeshi Sakata
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Publication number: 20060273405Abstract: In a masking pattern (a) for patterning word and data lines, length is changed between adjacent word lines so as to be shifted from each other at their tips, and furthermore, the tip of each word line is cut obliquely. It is thus possible to prevent the resist pattern from separation and contact of adjacent patterns. Consequently, it is also possible to prevent break failures of patterned lines and short failures between those patterned lines.Type: ApplicationFiled: August 16, 2006Publication date: December 7, 2006Inventors: Tomonori Sekiguchi, Toshihiko Tanaka, Toshiaki Yamanaka, Takeshi Sakata, Katsutaka Kimura
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Patent number: 7126868Abstract: 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: May 2, 2005Date of Patent: October 24, 2006Assignees: Renesas Technology Corp., Hitachi ULSI Systems Co., Ltd.Inventors: Hiroyuki Mizuno, Takeshi Sakata, Nobuhiro Oodaira, Takao Watanabe, Yusuke Kanno
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Patent number: 7116593Abstract: 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 word line 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: GrantFiled: September 13, 2002Date of Patent: October 3, 2006Assignee: Hitachi, Ltd.Inventors: Satoru Hanzawa, Kiyoo Itoh, Hideyuki Matsuoka, Motoyasu Terao, Takeshi Sakata
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Publication number: 20060208315Abstract: A field-effect semiconductor element implemented with a fewer number of elements and a reduced area and capable of storing data by itself without need for cooling at a cryogenic temperature, and a memory device employing the same. Gate-channel capacitance is set so small that whether or not a trap captures one electron or hole can definitely and distinctively be detected in terms of changes of a current of the semiconductor FET element. By detecting a change in a threshold voltage of the semiconductor element brought about by trapping of electron or hole in the trap, data storage can be realized at a room temperature.Type: ApplicationFiled: May 24, 2006Publication date: September 21, 2006Inventors: Kazuo Yano, Tomoyuki Ishii, Takashi Hashimoto, Koichi Seki, Masakazu Aoki, Takeshi Sakata, Yoshinobu Nakagome, Kan Takeuchi
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Patent number: 7106123Abstract: A semiconductor device including a level converter (LSC) is disclosed. The level converter comprises a voltage-up circuit (LSC1) that operates on low voltage of power supply (VDD) and steps up voltage enough to drive the level converter and a level converter circuit (LSC2) that operates on high voltage of power supply (VDDQ). The voltage-up circuit is capable of constantly generating 2×VDD so that the level converter can convert a low voltage of power supply (VDD) below 1 V to VDDQ. This voltage-up circuit can be configured only with MOSFET transistors produced by thin oxide film deposition, thus enabling high-speed operation. To facilitate designing a circuit for preventing a leakage current from occurring in the level converter during sleep mode of a low-voltage-driven circuit (CB1), the level converter circuit (LSC2) includes a leak protection circuit (LPC) that exerts autonomous control for leak prevention, dispensing with external control signals.Type: GrantFiled: April 29, 2005Date of Patent: September 12, 2006Assignee: Renesas Technology CorporationInventors: Yusuke Kanno, Hiroyuki Mizuno, Takeshi Sakata, Takao Watanabe
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Patent number: 7105873Abstract: In a masking pattern (a) for patterning word and data lines, length is changed between adjacent word lines so as to be shifted from each other at their tips, and furthermore, the tip of each word line is cut obliquely. It is thus possible to prevent the resist pattern from separation and contact of adjacent patterns. Consequently, it is also possible to prevent break failures of patterned lines and short failures between those patterned lines.Type: GrantFiled: October 29, 2002Date of Patent: September 12, 2006Assignee: Hitachi, Ltd.Inventors: Tomonori Sekiguchi, Toshihiko Tanaka, Toshiaki Yamanaka, Takeshi Sakata, Katsutaka Kimura