Patents by Inventor Kiyotsugu Ueda

Kiyotsugu Ueda 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: 5930197
    Abstract: A semiconductor memory device is provided which is able to supply data at high speed to a microprocessor (MPU) without being affected by the dispersion of power supply voltage, temperature and production process conditions. A semiconductor chip includes an address buffer, a decoder, a word driver, data lines, a sense amplifier, a main amplifier, an output buffer, and a PLL to which an external clock is applied. The PLL generates controls signals .PHI..sub.1 through .PHI..sub.7 with their phases shifted in turn, and supplies them to those internal circuits ranging from the address buffer to the output buffer. The PLL can control the phases of these control signals to be constant without being affected by the variations of temperature and power supply voltage. Thus, the internal circuits are precharged or equalized by the control signals, and then operated by the control signals to amplify data signal in turn.
    Type: Grant
    Filed: July 28, 1997
    Date of Patent: July 27, 1999
    Assignees: Hitachi, Ltd., Hitachi ULSI Engineering Corp.
    Inventors: Koichiro Ishibashi, Kunihiro Komiyaji, Kiyotsugu Ueda, Hiroshi Toyoshima
  • Patent number: 5740115
    Abstract: A semiconductor memory device is provided which is able to supply data at high speed to a microprocessor (MPU) without being affected by the dispersion of power supply voltage, temperature and production process conditions. A semiconductor chip includes an address buffer, a decoder, a word driver, data lines, a sense amplifier, a main amplifier, an output buffer, and a PLL to which an external clock is applied. The PLL generates controls signals .PHI..sub.1 through .PHI..sub.7 with their phases shifted in turn, and supplies them to those internal circuits ranging from the address buffer to the output buffer. The PLL can control the phases of these control signals to be constant without being affected by the variations of temperature and power supply voltage. Thus, the internal circuits are precharged or equalized by the control signals, and then operated by the control signals to amplify data signal in turn.
    Type: Grant
    Filed: July 6, 1995
    Date of Patent: April 14, 1998
    Assignees: Hitachi, Ltd., Hitachi ULSI Engineering Corporation
    Inventors: Koichiro Ishibashi, Kunihiro Komiyaji, Kiyotsugu Ueda, Hiroshi Toyoshima
  • Patent number: 5519662
    Abstract: In a semiconductor memory device, amplification of data is realized with a high speed without influences of fluctuations at fabrication. Potentials of a common data line pair are set at a reference voltage by current negative feedback of differential amplifiers. In this way signal amplitude in the common data line pair is decreased. A current from a memory cell is transformed into a voltage by transistors in a negative feedback loop. Even if there are fluctuations or an offset voltage in the differential amplifiers, it is possible to decrease the signal amplitude in the common data line pair and to realize a high speed data amplification with low electric power consumption.
    Type: Grant
    Filed: November 15, 1994
    Date of Patent: May 21, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Koichiro Ishibashi, Kiyotsugu Ueda, Kunihiro Komiyaji
  • Patent number: 5088065
    Abstract: Information read out from a memory cell of a static type semiconductor memory is subjected to multi-stage sense amplification in an initial stage sense amplifier, a post-stage sense amplifier and a main amplifier and then transmitted to the input of an output buffer circuit. Since an equalizing circuit is connected to the complementary inputs of each stage of the multi-stage sense amplifier, an inverse information read operation can be executed at high speed. Initially, the initial stage sense amplifier, the post-stage sense amplifier and the main amplifier are controlled to operate in high amplification gain conditions so as to execute high speed sense amplification and thereafter controlled to operate in such low power consumption conditions that the read-out information output obtained by the high speed sense amplification will not disappear.
    Type: Grant
    Filed: October 5, 1990
    Date of Patent: February 11, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Shoji Hanamura, Masaaki Kubotera, Katsuro Sasaki, Takao Oono, Kiyotsugu Ueda
  • Patent number: 4891792
    Abstract: Information read out from a memory cell of a static type semiconductor memory is subjected to multi-stage sense amplification in an initial stage sense amplifier, a post-stage snese amplifier and a main amplifier and then transmitted to the input of an output buffer circuit. Since an equalizing circuit is connected to the complementary inputs of each stage of the multi-stage sense amplifier, an inverse information read operation can be executed at high speed. Initially, the initial stage sense amplifier, the post-stage sense amplifier and the main amplifier are controlled to operate in high amplification gain conditions so as to execute high speed sense amplification and thereafter controlled to operate in such low power consumption conditions that the read-out information output obtained by the high speed sense amplification will not disappear.
    Type: Grant
    Filed: July 6, 1988
    Date of Patent: January 2, 1990
    Assignees: Hitachi, Ltd., Hitachi VLSI Engineering Corp.
    Inventors: Shoji Hanamura, Masaaki Kubotera, Katsuro Sasaki, Takao Oono, Kiyotsugu Ueda
  • Patent number: 4797717
    Abstract: Each of the memory cells in a SRAM includes two driver MOS transistors, two transfer gate MOS transistors and two load resistances. The gate electrode layers of the MOS transistors are formed from a first-level conductive layer provided on the surface of a semiconductor substrate. The source regions of the two driver MOS transistors in each memory cell are connected in common and further connected to a ground potential point through a second-level conductive layer. The two load resistances in each memory cell are formed from a third-level high-resistance material layer. The second-level conductive layer is formed from a low-resistance material layer. Thus the resistance of the sources of the two driver MOS transistors is lowered.
    Type: Grant
    Filed: April 17, 1987
    Date of Patent: January 10, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Koichiro Ishibashi, Osamu Minato, Toshiaki Masuhara, Yoshio Sakai, Toshiaki Yamanaka, Naotaka Hashimoto, Shoji Hanamura, Nobuyuki Moriwaki, Shigeru Honjyo, Kiyotsugu Ueda