Patents by Inventor Suguru Tachibana

Suguru Tachibana 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: 6342710
    Abstract: A semiconductor integrated circuit, particularly a circuit for a high-speed low-power-consumption table look-aside buffer mounted in a microprocessor LSI. The semiconductor integrated circuit is provided with field effect transistors for comparing inputted multibit data signals with stored data and a coincidence-detecting signal line (25) to which current is applied at least while the data signals are compared with stored data. When the data signals coincide with the stored data, the transistors (26) conduct. The number of transistors (26) is equal to that of the inputted data signals. The drains of the transistors (260 are connected in parallel, and the sources are also connected in parallel and supplied with a predetermined voltage. By the integrated circuit, whether or not the inputted data signals coincide with the stored data is detected by detecting the potential of the coincidence-detecting signal line (25) upon a change of the applied current.
    Type: Grant
    Filed: March 9, 2000
    Date of Patent: January 29, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Hisayuki Higuchi, Suguru Tachibana, Koichiro Ishibashi, Keijiro Uehara
  • Patent number: 6121646
    Abstract: A semiconductor integrated circuit, particularly a circuit for a high-speed low-power-consumption table look-aside buffer mounted in a microprocessor LSI. The semiconductor integrated circuit is provided with field effect transistors for comparing inputted multibit data signals with stored data and a coincidence-detecting signal line (25) to which current is applied at least while the data signals are compared with stored data. When the data signals coincide with the stored data, the transistors (26) conduct. The number of transistors (26) is equal to that of the inputted data signals. The drains of the transistors (260 are connected in parallel, and the sources are also connected in parallel and supplied with a predetermined voltage. By the integrated circuit, whether or not the inputted data signals coincide with the stored data is detected by detecting the potential of the coincidence-detecting signal line (25) upon a change of the applied current.
    Type: Grant
    Filed: December 5, 1997
    Date of Patent: September 19, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Hisayuki Higuchi, Suguru Tachibana, Koichiro Ishibashi, Keijiro Uehara
  • Patent number: 5943284
    Abstract: A memory structure/circuit has at least two memory cell arrays connected to each other in a hierarchy. The bit lines of the two or more memory cell arrays are connected by hierarchy switches. The memory cells of one of the arrays can be read out faster than the others by using the hierarchy switches to select one array without selecting the other arrays. So the data that is read with higher frequency can be selectively read out faster if it is stored in the faster access memory array. If the data in the faster access memory cell array includes a copy of the data in the other array, it can be used as a cache memory. A tag array and data array in combination that are connected to another tag array and data array in combination through hierarchy switch connections can provide a cache memory that is direct mapped or set associative, and also full associative.
    Type: Grant
    Filed: August 29, 1996
    Date of Patent: August 24, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Mizuno, Suguru Tachibana, Koichiro Ishibashi, Kenichi Osada
  • Patent number: 5253197
    Abstract: In a first embodiment of a CAM (Content Addressable Memory) or cache memory of the present invention disclosed herein, comparing information stored in a memory cell with comparison input information is accomplished in a comparison circuit without first converting a readout current from the memory cell into voltage information. In another embodiment, a matching detection between first stored information outputted from a first memory cell array and second stored information outputted from a second memory cell array is accomplished by an integrally formed sensing and matching detection circuit which is characterized as having both sensing and matching detection capabilities. That is, the sensing and matching detection circuit senses both stored information and thereafter detects matching based on a sensing result.
    Type: Grant
    Filed: September 11, 1990
    Date of Patent: October 12, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Makoto Suzuki, Suguru Tachibana, Hisayuki Higuchi, Katsuhiro Shimohigashi, Takehisa Hayashi, Makoto Hanawa, Tadahiko Nishimukai
  • Patent number: 5218567
    Abstract: A cache memory apparatus made up of a memory cell array (300) and a match detection circuit is disclosed. The match detection circuit produces a detection signal related to whether a search data coincides with a data read out of the memory cell array (300). The match detection circuit applies complementary signals (d, d) of the data read from the memory cell array (300) to the bases of bipolar differential transistors (10, 11), the gates of a pair of field effect transistors (16, 17) are supplied with complementary signals (a, a) of the search data, and the bases of a pair of emitter-follower transistors (12, 13) are connected to the collectors of the bipolar differential transistors (10, 11), thereby producing a detection signal (HITO) from the jointly-connected emitters thereof.
    Type: Grant
    Filed: November 7, 1991
    Date of Patent: June 8, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Makoto Suzuki, Suguru Tachibana, Hisayuki Higuchi
  • Patent number: 5107141
    Abstract: An output circuit portion of a BiCMOS logic circuit adapted to operating on a low voltage has an npn transistor Q5 connected between the power source Vcc and an output N6, and has an npn transistor Q6 connected between the output N6 and ground potential GND. The base of the npn transistor Q5 is driven by the drain output of p-channel MOSFETs MP3, MP4, and the base of the npn transistor Q6 is driven by the drain output of p-channel MOSFET QP5. When the power source voltage Vcc drops, the voltage applied between the drain and the source of MOSFET MP5 becomes small by the effect of V.sub.BE of the transistor Q6, but the drain current of the MOSFET MP5 changes little. Therefore, the BiCMOS circuit operates at high speeds (see FIG. 1) even when the power source voltage drops.
    Type: Grant
    Filed: October 29, 1990
    Date of Patent: April 21, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Kazuo Yano, Mitsuru Hiraki, Hisayuki Higuchi, Suguru Tachibana, Makoto Suzuki, Katsuhiro Shimohigashi
  • Patent number: 4928265
    Abstract: Considering the dispersion in the access time of semiconductor memories, at least a first and a second memory circuit are connected to the output of a sense amplifier. The output of the sense amplifier is an input to these two memory circuits alternatively at different timings. The data stored in these memory circuits are alternately transferred to a data output circuit. Even when the access time becomes long, the desired sense data can be successively read out from the output of the data output circuit at a short time interval determined by the clock cycle. When the access time becomes short and even when a second data is generated from the output of the sense amplifier at the timing of transferring a first data in the first memory circuit to the data output circuit, the first data held in the first memory circuit is prevented from being renewed by the second data.
    Type: Grant
    Filed: November 2, 1988
    Date of Patent: May 22, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Hisayuki Higuchi, Noriyuki Homma, Makoto Suzuki, Suguru Tachibana