Patents by Inventor Shigetoshi Wakayama

Shigetoshi Wakayama 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: 20010007136
    Abstract: A semiconductor integrated circuit device has a command decoder for issuing a control command in accordance with a supplied control signal, a DRAM core, and a timing adjusting circuit for supplying the control command, set active for a predetermined period, as a DRAM control signal to the DRAM core. The timing adjusting circuit generates n different clocks that are respectively shifted in phase with respect to a supplied reference clock, and generates the DRAM control signal by setting the control command active in a prescribed operation cycle for only a period starting at a first predetermined clock pulse of a first clock of the n clocks and ending at a second predetermined clock pulse of a second clock of the n clocks. In this way, timing design with relatively high accuracy of adjustment can be done in a short period.
    Type: Application
    Filed: February 28, 2001
    Publication date: July 5, 2001
    Applicant: Fujitsu Limited
    Inventors: Hirotaka Tamura, Hisakatsu Araki, Shigetoshi Wakayama, Kohtaroh Gotoh
  • Patent number: 6247138
    Abstract: A semiconductor integrated circuit device has a command decoder for issuing a control command in accordance with a supplied control signal, a DRAM core, and a timing adjusting circuit for supplying the control command, set active for a predetermined period, as a DRAM control signal to the DRAM core. The timing adjusting circuit generates n different clocks that are respectively shifted in phase with respect to a supplied reference clock, and generates the DRAM control signal by setting the control command active in a prescribed operation cycle for only a period starting at a first predetermined clock pulse of a first clock of the n clocks and ending at a second predetermined clock pulse of a second clock of the n clocks. In this way, timing design with relatively high accuracy of adjustment can be done in a short period.
    Type: Grant
    Filed: June 8, 1998
    Date of Patent: June 12, 2001
    Assignee: Fujitsu Limited
    Inventors: Hirotaka Tamura, Hisakatsu Araki, Shigetoshi Wakayama, Kohtaroh Gotoh, Junji Ogawa
  • Publication number: 20010002178
    Abstract: A restoring circuit 24, provided for each of the memory blocks 191 and 192, having registers and a selector for selecting one of the present row address and the output of the registers, provides the output of the selector to a word decoder 26. The present row address is held in one of the registers. When amplification is started by a sense amplifier 15, transfer gates 10 and 11 connected between the bit lines BL1 and *BL1 and the sense amplifier 15 are turned off to decrease the load of the sense amplifier 15, the amplified signal is stored in a buffer memory cell circuit 18, and accessing is completed with omitting restoring to the memory cell 12. While the memory cell block 191 is not selected, the data held in the buffer memory cell circuit 18 is stored into the memory cell row addressed by the content of the selected register. The sense amplifier 15 has PMOS and NMOS sense amplifiers.
    Type: Application
    Filed: January 25, 2001
    Publication date: May 31, 2001
    Applicant: Fujitsu Limited
    Inventors: Shigetoshi Wakayama, Kohtaroh Gotoh, Miyoshi Saito, Junji Ogawa
  • Patent number: 6218713
    Abstract: A logical circuit device has a MOS transistor having a source region, a drain region, a channel region defined between the source region and the drain region, and a gate electrode formed above the channel region, respectively formed on a semiconductor substrate. The amplitude of a voltage applied to the gate electrode necessary for making the channel region conductive is not level throughout the channel region in the width direction. Using such a logical circuit device, flip-flop circuits and storage circuits of a multivalued logic type can be realized.
    Type: Grant
    Filed: July 17, 1997
    Date of Patent: April 17, 2001
    Assignee: Fujitsu Limited
    Inventor: Shigetoshi Wakayama
  • Patent number: 6205076
    Abstract: A restoring circuit 24, provided for each of the memory blocks 191 and 192, having registers and a selector for selecting one of the present row address and the output of the registers, provides the output of the selector to a word decoder 26. The present row address is held in one of the registers. When amplification is started by a sense amplifier 15, transfer gates 10 and 11 connected between the bit lines BL1 and *BL1 and the sense amplifier 15 are turned off to decrease the load of the sense amplifier 15, the amplified signal is stored in a buffer memory cell circuit 18, and accessing is completed with omitting restoring to the memory cell 12. While the memory cell block 191 is not selected, the data held in the buffer memory cell circuit 18 is stored into the memory cell row addressed by the content of the selected register. The sense amplifier 15 has PMOS and NMOS sense amplifiers.
    Type: Grant
    Filed: March 26, 1999
    Date of Patent: March 20, 2001
    Assignee: Fujitsu Limited
    Inventors: Shigetoshi Wakayama, Kohtaroh Gotoh, Miyoshi Saito, Junji Ogawa
  • Patent number: 6157688
    Abstract: A signal transmission system has a response time of a signal transmission line which is set approximately equal to or longer than the length of a transmitted symbol. More specifically, terminal resistance is set larger than the characteristic impedance of the signal transmission line, driver output resistance is set to a large value, or a damping resistor is provided in series with the signal transmission line. With this configuration, signal power can be reduced drastically.
    Type: Grant
    Filed: October 6, 1997
    Date of Patent: December 5, 2000
    Assignee: Fujitsu Limited
    Inventors: Hirotaka Tamura, Miyoshi Saito, Kohtaroh Gotoh, Shigetoshi Wakayama, Junji Ogawa, Hisakatsu Araki, Tsz-shing Cheung
  • Patent number: 6064244
    Abstract: A phase-locked loop circuit is constituted in such a manner that a delayed signal created by causing an input signal to loop through a delay stage a plurality of times is compared in terms of phase with the input signal, and an amount of delay in the delay stage is controlled in accordance with the comparison result of the delayed signal and the input signal. Therefore, the circuit size can be reduced with a reduced number of delay units constituting the delay stage.
    Type: Grant
    Filed: March 7, 1997
    Date of Patent: May 16, 2000
    Assignee: Fujitsu Limited
    Inventors: Shigetoshi Wakayama, Kohtaroh Gotoh, Miyoshi Saito, Junji Ogawa, Hirotaka Tamura