Patents by Inventor Akira Yamazaki

Akira Yamazaki 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).

  • Publication number: 20020047731
    Abstract: In a detector included in a VPP generating circuit in a DRAM, an external power supply potential is applied to the gate of an N-channel MOS transistor for regulating a through current of an inverter for outputting an inversion signal of an output signal of a comparator. Since a drain-source voltage of the N-channel MOS transistor can be set to be lower than a threshold voltage Vthn of the N-channel MOS transistor, an operation margin of the detector under conditions of a low voltage and a low temperature is made wider as compared with a conventional technique.
    Type: Application
    Filed: March 16, 2001
    Publication date: April 25, 2002
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Mako Okamoto, Yasuhiko Taito, Fukashi Morishita, Akira Yamazaki, Mihoko Akiyama, Nobuyuki Fujii
  • Patent number: 6373763
    Abstract: An equalizing circuit includes a plurality of N-channel MOS transistors for respectively setting a data line to a predetermined precharge voltage. The H-level voltage Vddb of a control signal for turning on these N-channel MOS transistors is set to a range higher than the sum of the precharge voltage and a transistor threshold voltage. A Vddb generation circuit steps up an external power-supply voltage and sets a voltage Vddb in a range lower than a step-up voltage for activating a word line.
    Type: Grant
    Filed: April 23, 2001
    Date of Patent: April 16, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasuhiko Taito, Akira Yamazaki, Fukashi Morishita, Nobuyuki Fujii, Mako Okamoto
  • Publication number: 20020033725
    Abstract: The clock generating circuit includes: an oscillator generating a reference clock signal; an EX-OR gate connected in a ring configuration; and first and second D latch circuits. The EX-OR gate inverts a clock signal to provide the inverted clock signal to the first D latch circuit when an activating signal is at H level. In this case, the clock signal is a clock signal having a clock cycle period of twice that of the reference clock signal. The EX-OR gate provides the clock signal direct to the first D latch circuit when the activating signal is set to L level. In this case, level transition of the clock signal is ceased. Hence, generation of a glitch in the clock signal is prevented from occurring.
    Type: Application
    Filed: February 27, 2001
    Publication date: March 21, 2002
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasuhiko Taito, Akira Yamazaki, Fukashi Morishita, Nobuyuki Fujii, Mihoko Akiyama, Mako Okamoto
  • Patent number: 6356484
    Abstract: A semiconductor memory device includes a DRAM, an SRAM and a bi-direction transfer gate circuit provided between SRAM and DRAM. SRAM array includes a plurality of sets of word lines. Each set is provided in each row of SRAM array and each word line in each set is connected to a different group of memory cells of an associated row. An address signal for the SRAM and an address signal for the DRAM are separately applied to an address buffer. The semiconductor memory device further includes an additional function control circuit for realizing a burst mode and a sleep mode. A data transfer path from DRAM to the SRAM and a data transfer path from the SRAM to the DRAM are separately provided in the bi-directional transfer gate circuit. Data writing paths and data reading paths are separately provided in the DRAM array. By the above described structure, operation of the buffer circuit is stopped in the sleep mode, reducing power consumption.
    Type: Grant
    Filed: January 10, 2000
    Date of Patent: March 12, 2002
    Assignees: Mitsubishi Denki Kabushiki Kaisha, Mitsubishi Electric Engineering Co., Ltd.
    Inventors: Katsumi Dosaka, Masaki Kumanoya, Yasuhiro Konishi, Katsumitsu Himukashi, Kouji Hayano, Akira Yamazaki, Hisashi Iwamoto, Hideaki Abe, Yasuhiro Ishizuka, Tsukasa Saika
  • Publication number: 20020027809
    Abstract: In a control voltage generating section for supplying a control voltage to a gate of a charge transfer gate for transferring charges received from a capacitor to an output node to generate an internal voltage, the amplitude of the control voltage is switched in accordance with a switch signal. An internal voltage generating circuit making it possible to improve design efficiency, reliability and yield and reduce power consumption is provided.
    Type: Application
    Filed: June 8, 2001
    Publication date: March 7, 2002
    Inventors: Nobuyuki Fujii, Fukashi Morishita, Akira Yamazaki, Yasuhiko Taito, Mihoko Akiyama, Mako Kobayashi
  • Publication number: 20020017946
    Abstract: Oscillation outputs which are different between detector signals output in a first detector circuit and a second detector circuit are obtained from a first ring oscillator and a second ring oscillator respectively corresponding to the detector circuits, and a selector selects and outputs one of the oscillation outputs. Accordingly, it is sufficient to provide only one pump circuit.
    Type: Application
    Filed: June 14, 2001
    Publication date: February 14, 2002
    Inventors: Nobuyuki Fujii, Fukashi Morishita, Mihoko Akiyama, Akira Yamazaki, Mako Kobayashi, Yasuhiko Taito
  • Patent number: 6345348
    Abstract: A memory includes an ROM portion storing information specific to the memory, and transfers the stored information to a memory controller via an output buffer and a sink link. The memory controller manages the characteristics of the memory, so that a memory system can be structured utilizing memories of different characteristics.
    Type: Grant
    Filed: February 11, 1997
    Date of Patent: February 5, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Naoya Watanabe, Akira Yamazaki
  • Publication number: 20020011883
    Abstract: With power-on detection circuits provided for a plurality of power supply voltages, a main power-on detection signal is maintained at the active state to reset an internal node while at least one of the power-on detection signals is active. In a multi-power semiconductor integrated circuit device, current consumption at the time of power-up is reduced.
    Type: Application
    Filed: February 12, 2001
    Publication date: January 31, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA, and MITSUBISHI ELECTRIC ENGINEERING COMPANY LIMITED
    Inventors: Akira Yamazaki, Fukashi Morishita, Yasuhiko Taito, Nobuyuki Fujii, Mihoko Akiyama, Mako Kobayashi
  • Publication number: 20020011826
    Abstract: A semiconductor device includes a constant voltage generation circuit generating a constant voltage commonly to reference voltages corresponding to a plurality of internal voltages. The plurality of reference voltages are generated from the common constant voltage. Thus, the semiconductor device for generating internal voltages is implemented, which allows reduction in layout area and decrease in test time for voltage adjustment.
    Type: Application
    Filed: January 16, 2001
    Publication date: January 31, 2002
    Applicant: Mitsubishi Denki Kabushiki Kaisha and Mitsubishi Electric Engineering Company Limited
    Inventors: Fukashi Morishita, Akira Yamazaki, Yasuhiko Taito, Nobuyuki Fujii, Mihoko Akiyama, Mako Kobayashi
  • Publication number: 20020008566
    Abstract: A plurality of pump modules are provided, the number of pump modules to be activated is changed depending on a mode of operation, and the number of pump modules to be activated is also adjusted with the specification of interest taken into consideration. There can be provided an internal voltage generation circuit occupying a small area and readily capable of accommodating a change in specification.
    Type: Application
    Filed: January 17, 2001
    Publication date: January 24, 2002
    Applicant: Mitsubishi Denki Kabushiki Kaisha and Mitsubishi Electric Engineering Company Limited
    Inventors: Yasuhiko Taito, Akira Yamazaki, Fukashi Morishita, Mako Kobayashi, Mihoko Akiyama, Nobuyuki Fujii
  • Publication number: 20020008502
    Abstract: In a VDC circuit, a differential amplifier compares a first reference potential with an internal supply potential to generate a control signal according to a result of the comparison. A constant current source transistor receives at its gate a second reference potential supplied through a path different from that of the first reference potential to operate for controlling an operation current value of the differential amplifier. A drive transistor changes conductance between a node for outputting the internal supply potential and a supply potential according to the control signal.
    Type: Application
    Filed: January 19, 2001
    Publication date: January 24, 2002
    Applicant: Mitsubish Denki Kabushiki Kaisha and Mitsubish Electric Engineering Company Limited
    Inventors: Mihoko Akiyama, Fukashi Morishita, Akira Yamazaki, Yasuhiko Taito, Mako Kobayashi, Nobuyuki Fujii
  • Patent number: 6333873
    Abstract: A semiconductor memory device receives an external control signal repeatedly generated independently of an access to the memory device. The memory device includes an internal voltage generator for generating a desired internal voltage in response to the control signal. The internal voltage generator includes a charge pump circuit responsive to the control signal. The internal voltage may provide a negative voltage such as a substrate bias voltage, or may be a positive voltage boosted over an operating power supply voltage and used as a boosted word line drive signal. This scheme eliminates an oscillator for generating a repeated clock signal to the charge pump circuit, leading to reduced current consumption and reduced chip area for the semiconductor memory device.
    Type: Grant
    Filed: September 29, 1997
    Date of Patent: December 25, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masaki Kumanoya, Katsumi Dosaka, Yasuhiro Konishi, Akira Yamazaki, Hisashi Iwamoto, Kouji Hayano
  • Publication number: 20010050590
    Abstract: A semiconductor integrated circuit device includes a reference voltage generating circuit that can be tuned without a circuit replacement when a process condition is varied. The reference voltage generating circuit is constituted such that two different circuit configurations having different temperature properties are switched by a first switch. In each of the circuit configurations, a switch control circuit in which tuning can be performed by switching a second switch generates a control signal based on a test mode and supplies the signal to the first switch for tuning. Thereafter, a fuse in the switch control circuit is blown off to generate a control signal, and reference voltage Vref is output.
    Type: Application
    Filed: January 12, 2001
    Publication date: December 13, 2001
    Applicant: Mitsubishi Denki Kabushiki Kaisha and
    Inventors: Mako Kobayashi, Fukashi Morishita, Mihoko Akiyama, Yasuhiko Taito, Akira Yamazaki, Nobuyuki Fujii
  • Publication number: 20010044874
    Abstract: A memory includes an ROM portion storing information specific to the memory, and transfers the stored information to a memory controller via an output buffer and a sink link. The memory controller manages the characteristics of the memory, so that a memory system can be structured utilizing memories of different characteristics.
    Type: Application
    Filed: February 11, 1997
    Publication date: November 22, 2001
    Inventors: NAOYA WATANABE, AKIRA YAMAZAKI
  • Publication number: 20010040827
    Abstract: A semiconductor memory device includes a DRAM, an SRAM and a bi-direction transfer gate circuit provided between SRAM and DRAM. SRAM array includes a plurality of sets of word lines. Each set is provided in each row of SRAM array and each word line in each set is connected to a different group of memory cells of an associated row. An address signal for the SRAM and an address signal for the DRAM are separately applied to an address buffer. The semiconductor memory device further includes an additional function control circuit for realizing a burst mode and a sleep mode. A data transfer path from DRUM to the SRAM and a data transfer path from the SRAM to the DRAM are separately provided in the bi-directional transfer gate circuit. Data writing paths and data reading paths are separately provided in the DRAM array. By the above described structure, operation of the buffer circuit is stopped in the sleep mode, reducing power consumption.
    Type: Application
    Filed: January 10, 2000
    Publication date: November 15, 2001
    Inventors: KATSUMI DOSAKA, MASAKI KUMANOYA, YASUHIRO KONISHI, KATSUMITSU HIMUKASHI, KOUJI HAYANO, AKIRA YAMAZAKI, HISASHI IWAMOTO, HIDEAKI ABE, YASUHIRO ISHIZUKA, TSUKASA SAIKI
  • Patent number: 6316985
    Abstract: A semiconductor integrated circuit device includes an oscillator generating a clock signal and a charge pump circuit. The charge pump circuit includes capacity elements and an output transistor. The capacity element boosts a voltage on a boost node. The transistor (clamp circuit) clamps the voltage level on the boost node to a constant value. The capacity element controls the gate voltage of the output transistor. The clamp circuit is used to suppress a voltage applied to the transistors and the MOS capacity element, and suppresses generation of hot carriers.
    Type: Grant
    Filed: March 16, 1999
    Date of Patent: November 13, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Mako Kobayashi, Akira Yamazaki
  • Patent number: 6310815
    Abstract: Subbanks are arranged in four regions of a DRAM macro having a rectangular shape, bank control circuits are arranged in a prescribed region between these subbanks, and internal read/write data buses are arranged in a region different from the region where the bank control circuits are arranged. Since there is no crossing of the bank control circuits and the internal read/write data buses, the bank control circuits can be efficiently arranged to reduce the layout area. Accordingly, a semiconductor integrated circuit device including multi-bank memories which operates stably at high speed can be provided without increase of an area occupied by a chip.
    Type: Grant
    Filed: August 7, 1998
    Date of Patent: October 30, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tadato Yamagata, Akira Yamazaki, Shigeki Tomishima, Yoshio Yukinari, Makoto Hatakenaka, Atsushi Miyanishi
  • Patent number: D452518
    Type: Grant
    Filed: June 6, 2000
    Date of Patent: December 25, 2001
    Assignee: Sony Corporation
    Inventor: Akira Yamazaki
  • Patent number: D456035
    Type: Grant
    Filed: June 14, 2001
    Date of Patent: April 23, 2002
    Assignee: Sony Corporation
    Inventors: Akira Yamazaki, Atsushi Kawase
  • Patent number: D456434
    Type: Grant
    Filed: June 25, 2001
    Date of Patent: April 30, 2002
    Assignee: Sony Corporation
    Inventor: Akira Yamazaki