Patents by Inventor Yoichiro Aihara

Yoichiro Aihara 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: 7428682
    Abstract: In relation to the built-in self-test circuit (BIST circuit) for testing CAM macros, the present invention is intended to provide a means to enable reduction in amount of materials as required for wiring channel region for signal distribution, buffer, FF, etc., and in number of LSI pins, and further, to facilitate mounting on chips. The data generators for CAM testing, inserted between the APG for RAMs and CAM macros, create data to write to the CAM macros by obtaining the address signals directly or by decoding the same signals. The APG is common to all the memory macros, and testing proper to each CAM can be carried out by changing over the operation of the inserted data generators by means of the control signal. The data generators are arranged in the proximity of the CAM macros, the circuits to be tested.
    Type: Grant
    Filed: January 20, 2006
    Date of Patent: September 23, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Yoichiro Aihara, Masahiko Nishiyama, Daisuke Sasaki
  • Publication number: 20060195743
    Abstract: In relation to the built-in self-test circuit (BIST circuit) for testing CAM macros, the present invention is intended to provide a means to enable reduction in amount of materials as required for wiring channel region for signal distribution, buffer, FF, etc., and in number of LSI pins, and further, to facilitate mounting on chips. The data generators for CAM testing, inserted between the APG for RAMs and CAM macros, create data to write to the CAM macros by obtaining the address signals directly or by decoding the same signals. The APG is common to all the memory macros, and testing proper to each CAM can be carried out by changing over the operation of the inserted data generators by means of the control signal. The data generators are arranged in the proximity of the CAM macros, the circuits to be tested.
    Type: Application
    Filed: January 20, 2006
    Publication date: August 31, 2006
    Inventors: Yoichiro Aihara, Masahiko Nishiyama, Daisuke Sasaki
  • Patent number: 7009862
    Abstract: Data lines (D0, D1) are shared by a first storage portion (MA) and a second storage portion (MB), and furthermore, a first transistor (MC0) coupled to a first comparison data portion (CD0) and a second transistor (MCA) coupled to the storage node of a first storage portion are connected in series to form a first comparing circuit (11), and a third transistor (MC1) coupled to a second comparison data line (CD1) and a fourth transistor (MCB) coupled to the storage node of the second storage portion are connected in series to form a second comparing circuit (12). Consequently, it is possible to enhance a symmetry in the layout of a diffusion layer and a wiring layer and to achieve the easiness of a layout in which a memory cell is line symmetrical with respect to a center line passing through a center thereof. Thus, a manufacturing process condition can easily be optimized and a variation in a manufacturing process can be reduced so that the microfabrication of the memory cell can be achieved.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: March 7, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Keiichi Higeta, Satoshi Iwahashi, Yoichiro Aihara, Shigeru Nakahara
  • Publication number: 20050146947
    Abstract: Data lines (D0, D1) are shared by a first storage portion (MA) and a second storage portion (MB), and furthermore, a first transistor (MC0) coupled to a first comparison data portion (CD0) and a second transistor (MCA) coupled to the storage node of a first storage portion are connected in series to form a first comparing circuit (11), and a third transistor (MC1) coupled to a second comparison data line (CD1) and a fourth transistor (MCB) coupled to the storage node of the second storage portion are connected in series to form a second comparing circuit (12). Consequently, it is possible to enhance a symmetry in the layout of a diffusion layer and a wiring layer and to achieve the easiness of a layout in which a memory cell is line symmetrical with respect to a center line passing through a center thereof. Thus, a manufacturing process condition can easily be optimized and a variation in a manufacturing process can be reduced so that the microfabrication of the memory cell can be achieved.
    Type: Application
    Filed: December 15, 2004
    Publication date: July 7, 2005
    Inventors: Keiichi Higeta, Satoshi Iwahashi, Yoichiro Aihara, Shigeru Nakahara