Patents by Inventor Toshihiko Yokota

Toshihiko Yokota 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: 8161445
    Abstract: A novel logic design method for avoiding wiring congestion. According to the novel logic design method, an original gate having multiple inputs coming from different directions and having multiple outputs coming to different directions can be transformed to a logic block that has an input stage and an output stage. The gates of the input stage receive signals from the multiple inputs of the original gate. The gates of the output stage send signals to the multiple outputs of the original gate. Each gate of the input stage is placed in a vicinity of its inputs. Each gate of the output stage is placed in a vicinity of its outputs. The gates of the input and output stages are functionally equivalent to the original gate.
    Type: Grant
    Filed: January 17, 2008
    Date of Patent: April 17, 2012
    Assignee: International Business Machines Corporation
    Inventors: Chaitra M. Bhat, Chandrika Madhwacharya, Atsushi Sugai, Toshihiko Yokota
  • Patent number: 8006210
    Abstract: A novel logic design method for avoiding wiring congestion. According to the novel logic design method, an original gate having multiple inputs coming from different directions and having multiple outputs coming to different directions can be transformed to a logic block that has an input stage and an output stage. The gates of the input stage receive signals from the multiple inputs of the original gate. The gates of the output stage send signals to the multiple outputs of the original gate. Each gate of the input stage is placed in a vicinity of its inputs. Each gate of the output stage is placed in a vicinity of its outputs. The gates of the input and output stages are functionally equivalent to the original gate.
    Type: Grant
    Filed: January 15, 2008
    Date of Patent: August 23, 2011
    Assignee: International Business Machines Corporation
    Inventors: Chaitra M. Bhat, Chandrika Madhwacharya, Atsushi Sugai, Toshihiko Yokota
  • Patent number: 7930608
    Abstract: An integrated circuit for controlling voltage fluctuations. The integrated circuit includes a plurality of clock buffers and latches synchronously operated in accordance with operating clock signals distributed via the clock buffers. The circuit comprises a mechanism for performing an At Speed Test to shift data that are initially set for the latches in accordance with the operating clock signals to succeeding latches, respectively. It also has a timing designation circuit for enabling a clock signal pulse when a first output signal pulse is active. In addition, it includes a ring-type oscillator to consume current in the period during which the first output signal is active. The ring-type oscillator includes a delay control input terminal. The oscillation cycle of the ring-type oscillator is selectively adjusted by adjusting an input of the delay control input terminal.
    Type: Grant
    Filed: February 22, 2008
    Date of Patent: April 19, 2011
    Assignee: International Business Machines Corporation
    Inventor: Toshihiko Yokota
  • Patent number: 7793183
    Abstract: Embodiments of the present invention provide a microcomputer on which a plurality of ICs (Integrated Circuits) connected from one another by a source-synchronous interface is mounted.
    Type: Grant
    Filed: June 8, 2006
    Date of Patent: September 7, 2010
    Assignee: International Business Machines Corporation
    Inventors: Toshihiko Yokota, Ken Namura, Mitsuru Sugimoto
  • Patent number: 7752586
    Abstract: A design structure for an integrated circuit which includes: a first flip-flop which is capable of flushing and which operates by using a first clock signal CLK 1; a second flip-flop DFF 2 which operates by using a second clock signal CLK 2, and which is connected to the first flip flop; and a third flip-flop DFF 3 which operates by using the second clock signal CLK 2, and which is connected to the first flip-flop. A test on a path between the first and second flip-flops is carried out in a manner that test data is released and captured on receipt of the clock signal CLK 2 between the second flip-flop DFF 2 and the third flip-flop DFF 3 via the first flip-flop DFF 1, and that the test data is flushed by the first flip-flop DFF 1.
    Type: Grant
    Filed: November 20, 2007
    Date of Patent: July 6, 2010
    Assignee: International Business Machines Corporation
    Inventor: Toshihiko Yokota
  • Patent number: 7752513
    Abstract: A method and integrated circuit for LSSD testing. The integrated circuit includes a plurality of clock domains supplied with test clocks from separate clock generation circuits. In each clock domain, a scan latch at a clock domain boundary receiving an input from another clock domain includes a master latch for latching an input in response to a first clock, a slave latch for latching an output from the master latch in response to a second clock, a selector for supplying the master latch with a system input when the mode selection signal is at a second level, and a clock control circuit for turning off the first clock when the mode selection signal transits from the first level to the second level.
    Type: Grant
    Filed: February 7, 2007
    Date of Patent: July 6, 2010
    Assignee: International Business Machines Corporation
    Inventors: Ken Namura, Sanae Seike, Toshihiko Yokota
  • Publication number: 20090132973
    Abstract: A design structure for an integrated circuit which includes: a first flip-flop which is capable of flushing and which operates by using a first clock signal CLK 1; a second flip-flop DFF 2 which operates by using a second clock signal CLK 2, and which is connected to the first flip flop; and a third flip-flop DFF 3 which operates by using the second clock signal CLK 2, and which is connected to the first flip-flop. A test on a path between the first and second flip-flops is carried out in a manner that test data is released and captured on receipt of the clock signal CLK 2 between the second flip-flop DFF 2 and the third flip-flop DFF 3 via the first flip-flop DFF 1, and that the test data is flushed by the first flip-flop DFF 1.
    Type: Application
    Filed: November 20, 2007
    Publication date: May 21, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventor: Toshihiko Yokota
  • Publication number: 20090119561
    Abstract: Embodiments of the present invention provide a microcomputer on which a plurality of ICs (Integrated Circuits) connected from one another by a source-synchronous interface is mounted.
    Type: Application
    Filed: June 8, 2006
    Publication date: May 7, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Toshihiko Yokota, Ken Namura, Mitsuru Sugimoto
  • Publication number: 20080209292
    Abstract: An integrated circuit and related method for controlling voltage fluctuations. The integrated circuit includes a plurality of clock buffers and a plurality of latches synchronously operated in accordance with operating clock signals distributed via the clock buffers. The circuit comprises a mechanism for performing an At Speed Test to shift data that are initially set for the latches in accordance with the operating clock signals to succeeding latches, respectively. It also has a timing designation circuit for generating a first output signal that is active for a period from a predetermined time, which is after the integrated circuit is powered on and before an operating clock signal for the At Speed Test is generated, to a time when the operating clock signal is generated.
    Type: Application
    Filed: February 22, 2008
    Publication date: August 28, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventor: Toshihiko Yokota
  • Publication number: 20080134110
    Abstract: A novel logic design method for avoiding wiring congestion. According to the novel logic design method, an original gate having multiple inputs coming from different directions and having multiple outputs coming to different directions can be transformed to a logic block that has an input stage and an output stage. The gates of the input stage receive signals from the multiple inputs of the original gate. The gates of the output stage send signals to the multiple outputs of the original gate. Each gate of the input stage is placed in a vicinity of its inputs. Each gate of the output stage is placed in a vicinity of its outputs. The gates of the input and output stages are functionally equivalent to the original gate.
    Type: Application
    Filed: January 17, 2008
    Publication date: June 5, 2008
    Inventors: Chaitra M. Bhat, M. Chandrika, Atsushi Sugai, Toshihiko Yokota
  • Publication number: 20080115094
    Abstract: A novel logic design method for avoiding wiring congestion. According to the novel logic design method, an original gate having multiple inputs coming from different directions and having multiple outputs coming to different directions can be transformed to a logic block that has an input stage and an output stage. The gates of the input stage receive signals from the multiple inputs of the original gate. The gates of the output stage send signals to the multiple outputs of the original gate. Each gate of the input stage is placed in a vicinity of its inputs. Each gate of the output stage is placed in a vicinity of its outputs. The gates of the input and output stages are functionally equivalent to the original gate.
    Type: Application
    Filed: January 15, 2008
    Publication date: May 15, 2008
    Inventors: Chaitra Bhat, M. Chandrika, Atsushi Sugai, Toshihiko Yokota
  • Patent number: 7356797
    Abstract: A novel logic design method for avoiding wiring congestion. According to the novel logic design method, an original gate having multiple inputs coming from different directions and having multiple outputs coming to different directions can be transformed to a logic block that has an input stage and an output stage. The gates of the input stage receive signals from the multiple inputs of the original gate. The gates of the output stage send signals to the multiple outputs of the original gate. Each gate of the input stage is placed in a vicinity of its inputs. Each gate of the output stage is placed in a vicinity of its outputs. The gates of the input and output stages are functionally equivalent to the original gate.
    Type: Grant
    Filed: June 14, 2005
    Date of Patent: April 8, 2008
    Assignee: International Business Machines Corporation
    Inventors: Chaitra M. Bhat, M. Chandrika, Atsushi Sugai, Toshihiko Yokota
  • Publication number: 20070198882
    Abstract: A method and integrated circuit for LSSD testing. The integrated circuit includes a plurality of clock domains supplied with test clocks from separate clock generation circuits. In each clock domain, a scan latch at a clock domain boundary receiving an input from another clock domain includes a master latch for latching an input in response to a first clock, a slave latch for latching an output from the master latch in response to a second clock, a selector for supplying the master latch with a system input when the mode selection signal is at a second level, and a clock control circuit for turning off the first clock when the mode selection signal transits from the first level to the second level.
    Type: Application
    Filed: February 7, 2007
    Publication date: August 23, 2007
    Inventors: Ken Namura, Sanae Seike, Toshihiko Yokota
  • Publication number: 20070124635
    Abstract: An object of the present invention is to realize an at-speed test on a latch-to-latch path (a cross domain path) between different clock domains. In order to achieve the object, the present invention provides an integrated circuit which includes: a first flip-flop which is capable of flushing and which operates by using a first clock signal CLK 1; a second flip-flop DFF 2 which operates by using a second clock signal CLK 2, and which is connected to the first flip flop; and a third flip-flop DFF 3 which operates by using the second clock signal CLK 2, and which is connected to the first flip-flop. A test on a path between the first and second flip-flops is carried out in a manner that test data is released and captured on receipt of the clock signal CLK 2 between the second flip-flop DFF 2 and the third flip-flop DFF 3 via the first flip-flop DFF 1, and that the test data is flushed by the first flip-flop DFF 1.
    Type: Application
    Filed: November 1, 2006
    Publication date: May 31, 2007
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventor: Toshihiko Yokota
  • Publication number: 20060282809
    Abstract: A novel logic design method for avoiding wiring congestion. According to the novel logic design method, an original gate having multiple inputs coming from different directions and having multiple outputs coming to different directions can be transformed to a logic block that has an input stage and an output stage. The gates of the input stage receive signals from the multiple inputs of the original gate. The gates of the output stage send signals to the multiple outputs of the original gate. Each gate of the input stage is placed in a vicinity of its inputs. Each gate of the output stage is placed in a vicinity of its outputs. The gates of the input and output stages are functionally equivalent to the original gate.
    Type: Application
    Filed: June 14, 2005
    Publication date: December 14, 2006
    Applicant: International Business Machines Corporation
    Inventors: Chaitra Bhat, M. Chandrika, Atsushi Sugai, Toshihiko Yokota