Patents by Inventor Seiji Enomoto

Seiji Enomoto 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: 4899310
    Abstract: A semiconductor memory device having a register and a memory cell array includes a controlling circuit for disconnecting an input/output circuit from a data bus and turning OFF a transfer gate provided between the register and data bus in a first operation mode and for connecting the input/output circuit to the data bus and turning ON the transfer gate in a second operation mode. In the first operation mode, a data read or write operation is performed between the memory cell array and an external circuit, and alternatively in the second operation mode the data read or write operation is performed between the register and the external circuit.
    Type: Grant
    Filed: June 22, 1988
    Date of Patent: February 6, 1990
    Assignees: Fujitsu Limited, Fujitsu VLSI Limited
    Inventors: Fumio Baba, Kazuya Kobayashi, Seiji Enomoto, Hiroaki Ogawa
  • Patent number: 4602356
    Abstract: A semiconductor memory device operates under a so-called address multiplex access method. A row part of the device is enabled by receiving a row address strobe (RAS) signal. A column part of the device is enabled by simultaneously receiving both a column address strobe (CAS) signal and a timing control signal supplied from the row part during its enable state. A column address buffer in the column part is enabled by simultaneously receiving both the CAS signal and a timing control signal. The timing control signal is produced from a circuit when it detects and holds the RAS signal.
    Type: Grant
    Filed: December 1, 1982
    Date of Patent: July 22, 1986
    Assignee: Fujitsu Limited
    Inventors: Shigeki Nozaki, Yoshihiro Takemae, Seiji Enomoto
  • Patent number: 4550289
    Abstract: A semiconductor integrated circuit (IC) device includes therein a test circuit. The test circuit operates to distinguish the power source level during the testing or ground level occurring at an internal node located inside the semiconductor chip. The test circuit includes a series-connected MIS transistor and an MIS diode. The gate of the MIS transistor is connected to the internal node. The MIS diode is connected to an external input/output (I/O) pin. The level at the internal node, i.e., the power source level or the ground level, can be distinguished by a first voltage level or a second voltage level applied to the external I/O pin, whichever enables a current to be drawn from the external I/O pin.
    Type: Grant
    Filed: December 27, 1982
    Date of Patent: October 29, 1985
    Assignee: Fujitsu Limited
    Inventors: Katsuhiko Kabashima, Yoshihiro Takemae, Shigeki Nozaki, Tsuyoshi Ohira, Hatsuo Miyahara, Masakazu Kanai, Seiji Enomoto
  • Patent number: 4504929
    Abstract: A dynamic semiconductor memory device provides a selected real cell, which is connected to a first of a pair of bit lines connected to a sense amplifier, and a dummy cell which is connected to a second of the pair of bit lines so as to perform a read-out operation. The dynamic semiconductor memory cell further provides an active restore circuit for pulling up the bit line potential of the bit line on the higher potential side of the pair of bit lines, in which the potential difference is increased by the read-out operation. The dynamic semiconductor cell can also provide a write-in circuit for charging the selected real cell through the bit line. A test power source pad is provided in the active restore circuit or the write in circuit so that when the reference level of the real cell is tested an optional power source can be applied from the test power source pad instead of from a normal power source.
    Type: Grant
    Filed: November 24, 1982
    Date of Patent: March 12, 1985
    Assignee: Fujitsu Limited
    Inventors: Yoshihiro Takemae, Tsuyoshi Ohira, Seiji Enomoto
  • Patent number: 4496850
    Abstract: A semiconductor circuit for driving a clock signal line comprising a first circuit for pulling up the potential of the clock signal line to the source voltage and a second circuit for pulling down the potential of the clock signal line to a lower voltage. A capacitor is connected to the clock signal line for receiving a potential push signal and pushing the potential of the clock signal line higher than the source voltage. The capacitor performs the function of capacitance only after the potential of the clock signal line is raised to the source voltage. The operational speed of a dynamic memory device associated with the semiconductor device is then enhanced.
    Type: Grant
    Filed: February 10, 1982
    Date of Patent: January 29, 1985
    Assignee: Fujitsu Limited
    Inventors: Yoshihiro Takemae, Shigeki Nozaki, Katsuhiko Kabashima, Seiji Enomoto
  • Patent number: 4482825
    Abstract: In a semiconductor device having a signal line on which a voltage higher than the voltage supply is generated, a conductive layer following the potential variance of the voltage supply is positioned under an insulating film directly below the signal line in order to make the level of the signal line follow the potential variance of the voltage supply.
    Type: Grant
    Filed: December 2, 1981
    Date of Patent: November 13, 1984
    Assignee: Fujitsu Limited
    Inventors: Shigeki Nozaki, Yoshihiro Takemae, Katsuhiko Kabashima, Seiji Enomoto
  • Patent number: 4458337
    Abstract: A buffer circuit comprises a flip-flop which is receives an external input via a first input circuit and a reference voltage via a second input circuit. Internal complementary outputs are then produced via an output circuit. The flip-flop cooperates with at least one level setting device by way of a second input circuit. The level setting device functions to produce a voltage level to deactivate the second input circuit during activation of the flip-flop.
    Type: Grant
    Filed: March 3, 1982
    Date of Patent: July 3, 1984
    Assignee: Fujitsu Limited
    Inventors: Yoshihiro Takemae, Shigeki Nozaki, Tsutomu Mezawa, Katsuhiko Kabashima, Seiji Enomoto
  • Patent number: 4451908
    Abstract: An address buffer for a dynamic memory includes a flip-flop. The flip-flop is coupled at its one input/output terminal with both a first input circuit and a third input circuit connected in parallel with each other and at its other input/output terminal with a second input circuit. The second input circuit receives a reference voltage and is activated by an external address timing clock during a normal operation mode. The first input circuit is also activated by the external address timing clock, but receives an external address. The third input circuit receives an internal refresh address and is activated by an internal refresh address. The address buffer cooperates with a switcher which produces the internal refresh address timing clock and the external address timing clock, alternatively, by switching a basic timing clock generated by an address drive clock generator.
    Type: Grant
    Filed: March 3, 1982
    Date of Patent: May 29, 1984
    Assignee: Fujitsu Limited
    Inventors: Yoshihiro Takemae, Shigeki Nozaki, Katsuhiko Kabashima, Seiji Enomoto, Tsutomu Mezawa
  • Patent number: 4447745
    Abstract: A semiconductor circuit used as a buffer circuit having an input stage circuit for receiving an input clock signal and an inverted input clock signal, a bootstrap circuit including a transistor for receiving the output of the input stage circuit and for maintaining the gate voltage of the transistor at a high level during the standby period, and an output circuit, including a transistor which is switched on and off by the output of the bootstrap circuit, for generating an output clock signal; the semiconductor circuit further comprising a current leak circuit for maintaining, during the standby period, the voltage of a point in the semiconductor circuit which is charged during the standby period at the value corresponding to the voltage of the power source, whereby the delay of the output clock signal, caused of the fluctuation by the voltage of the power supply during the standby period, is improved and then the high speed access time in the dynamic memory is carried out.
    Type: Grant
    Filed: November 18, 1981
    Date of Patent: May 8, 1984
    Assignee: Fujitsu Limited
    Inventors: Yoshihiro Takemae, Seiji Enomoto, Shigeki Nozaki, Tsutomu Mezawa, Katsuhiko Kabashima
  • Patent number: 4430581
    Abstract: A semiconductor circuit consisting of a dynamic-type circuit and a bias-voltage generating circuit. The bias-voltage generating circuit is comprised of a first bias-voltage generator and a second bias-voltage generator. The first generator absorbs a variable substrate current, the magnitude of which is proportional to the operating frequency of the dynamic-type circuit, while the second generator absorbs a substrate current, the magnitude of which is not proportional to the operating frequency of the dynamic-type circuit. Alternately, both portions of the substrate current may be absorbed via the same circuitry.
    Type: Grant
    Filed: May 13, 1981
    Date of Patent: February 7, 1984
    Assignee: Fujitsu Limited
    Inventors: Jun-ichi Mogi, Kiyoshi Miyasaka, Seiji Enomoto, Shigeki Nozaki
  • Patent number: 4378438
    Abstract: A tray for identifying isolated microorganisms consisting of a plastic or glass tray body and a transparent cover, the body surface of which has two kinds of hollows for bacterial suspensions. One is formed horizontally across the surface of the tray and the other is composed of number of small wells long and slender, put parallel and rectangular to previous hollow. Each of the small cells communicates over crest barrier to hollow put horizontally. With this tray, microorganisms can be exactly and easily identified.
    Type: Grant
    Filed: October 29, 1981
    Date of Patent: March 29, 1983
    Assignee: Eiken Chemical Co., Ltd.
    Inventors: Toshikatsu Masaki, Seiji Enomoto, Michiya Kimura
  • Patent number: 4370419
    Abstract: A tray for identifying isolated microorganisms, comprising a plastic or glass tray body and a cover, the body surface of which has two kinds of hollow cells for bacterial suspension. One is formed horizontally across the surface of the tray and the other is composed of a number of long and slender, parallel small cells. Each of the small cells communicates over a crest barrier with another hollow cell. Each crest barrier is formed so that its top is lower in height than the upper surface of the partition wall of the tray body. With this tray, microorganisms can be exactly and easily identified by improving the accuracy of uniformly pouring bacterial suspension into respective cells for bacterial suspension.
    Type: Grant
    Filed: July 15, 1981
    Date of Patent: January 25, 1983
    Assignee: Eiken Chemical Co., Ltd.
    Inventors: Tamotsu Iida, Seiji Enomoto, Michiya Kimura
  • Patent number: 4224633
    Abstract: Self-aligned IGFET structure having a source region, a drain region and a gate electrode placed between the source and drain regions to define a channel region. The gate electrode is provided with an extended end portion on a relatively thick field oxide layer and having a length no less than a predetermined channel length on one side of the channel region so that the breakdown voltage is not decreased on that one side of the channel region.
    Type: Grant
    Filed: May 23, 1978
    Date of Patent: September 23, 1980
    Assignee: Fujitsu Limited
    Inventors: Jun-ichi Mogi, Kiyoshi Miyasaka, Seiji Enomoto