Patents by Inventor Masahiro Iwamura

Masahiro Iwamura 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: 5761150
    Abstract: There is provided a method of controlling an internal address signal of an RAM in which a late-write method is realized on a chip. Two sets of address registers for reading and writing are provided for each address and further a middle register is provided between the two sets of address registers. The middle register is controlled by a signal formed by obtaining the AND result of a clock signal and a write enable signal and the two sets of address registers for reading and writing are controlled only by the clock signal. A selection circuit selects outputs of the two sets of address registers as an input in accordance with the write enable signal to control an internal address.
    Type: Grant
    Filed: May 21, 1996
    Date of Patent: June 2, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Seigoh Yukutake, Kinya Mitsumoto, Takashi Akioka, Masahiro Iwamura, Noboru Akiyama
  • Patent number: 5742551
    Abstract: A constant current source is connected in series to a current source circuit including a MOS transistor which is used as a current source for a differential output amplifier circuit, an emitter follower circuit or a source follower circuit used with a semiconductor integrated circuit. In a multiplex circuit, an input signal is inputted to each of base terminals of a plurality of bipolar transistors. When one input signal is selected, the bipolar transistor corresponding to the selected input signal is made to be operable with an input signal from a signal input terminal by a control circuit. The bipolar transistors corresponding to the non-selection input signals are turned OFF irrespective of potential levels of the individual input signals by current drawing circuits.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: April 21, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Seigoh Yukutake, Yutaka Kobayashi, Takashi Akioka, Masahiro Iwamura
  • Patent number: 5734913
    Abstract: In semiconductor integrated circuit device and microprocessor including at least one functional circuit block, the start of operation of the functional circuit block is detected prior to the start of operation, the functional circuit block for which the start of operation has been detected is activated prior to the start of operation and inactivated after the termination of operation.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: March 31, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Iwamura, Shigeya Tanaka, Hideo Maejima, Tetsuo Nakano
  • Patent number: 5734616
    Abstract: A static RAM includes pre-amplifiers, which are made up solely of emitter-follower transistors having their collectors supplied with the power voltage, in one-to-one correspondence to sub common data line pairs which are connected by column switches to complementary data line pairs of memory arrays. The pre-amplifier is provided with a first switch which turns on during the selected state to connect the sub common data line pair to the bases of the transistors and a second switch which turns on during the unselected state to provide the bases with a certain bias voltage lower than the readout signal voltage on the sub common data line pair. The emitter-follower transistors have their emitters connected commonly to form common emitter lines, which are connected to pairs of input terminals of main amplifiers made up of CMOS transistors.
    Type: Grant
    Filed: August 8, 1996
    Date of Patent: March 31, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Hideto Kazama, Shuichi Miyaoka, Akihiko Emori, Kinya Mitsumoto, Tomoyuki Someya, Masahiro Iwamura, Noboru Akiyama
  • Patent number: 5680066
    Abstract: A semiconductor device which includes at least one of (1) an input buffer circuit formed of an input level converter and a non-inverting buffer circuit and an inverting buffer circuit each including BiCMOS circuitry which effects high-speed operation; (2) a decoder circuit formed of plural logic gates each of which is composed of the combination of MOS and bipolar circuitry; (3) a sense amplifier circuit including a multiemitter transistor; (4) a signal or address transition detector circuit which includes input circuits each receiving, for example, an address signal of a voltage amplitude and outputting a current amplitude signal in response to a change in level of the address signal, and a detector circuit connected thereto which has a cascode amplifier arranged such that it receives current amplitude signals at an input thereof and in which the cascode amplifier input is maintained at a substantially constant voltage, in which the detection circuit detects a transition of one or more of the current amplitu
    Type: Grant
    Filed: January 13, 1994
    Date of Patent: October 21, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Akioka, Masahiro Iwamura, Atsushi Hiraishi, Yuji Yokoyama, Nozomu Matsuzaki, Tatsumi Yamauchi, Yutaka Kobayashi, Nobuyuki Gotou, Akira Ide, Masahiro Yamamura, Hideaki Uchida
  • Patent number: 5675548
    Abstract: An arrangement which is particularly effective for decoders in semiconductor memory circuits which use, for example, common NMOS to receive one input for a plurality of logic decoder gates is provided includes a plurality of logic gates each having a first input terminal for respectively receiving first input signals and each being coupled to a common node. In one embodiment, first and second switching elements are also coupled to the common node. The first and second switching elements are both coupled to a second input terminal for receiving a second input signal which is common to the plurality of logic gates, and both operate complementary to one another in response to the second input signal. An improved read/write arrangement is also provided for such semiconductor memory circuit which includes circuitry to prevent connection of a common read line to the data lines during the writing operation. This enhances the writing speed by removing the load of the common read line during writing.
    Type: Grant
    Filed: February 29, 1996
    Date of Patent: October 7, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Yuji Yokoyama, Takashi Akioka, Masahiro Iwamura, Atsushi Hiraishi, Yutaka Kobayashi, Tatsumi Yamauchi, Shigeru Takahashi, Nobuyuki Gotou, Akira Ide
  • Patent number: 5661693
    Abstract: A synchronous memory device is provided in which the cycle time is shorter than conventional memory devices. For example, by providing an output latch in a sense amplifier on a bit line, the time period from input of a clock signal to latching data in the output latch is shortened. In case of plural bit lines, a selector for selecting data in a plural output latch and a latch for latching a sense amplifier selection are provided.
    Type: Grant
    Filed: November 22, 1995
    Date of Patent: August 26, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Akioka, Noboru Akiyama, Masahiro Iwamura, Seigoh Yukutake
  • Patent number: 5657264
    Abstract: A semiconductor memory comprises a write driver which is provided to correspond to respective data line and by which data lines connected with a memory cell through the control of a word line are driven in a write operation. The write driver includes MOSFETs of first group and MOSFETs of second group. In a case where a write enable signal does not designate the write operation, the MOSFETs of the first group are normally in ON states to pull up the data lines. Besides, in a case where the write enable signal designates the write operation, each of them operates in accordance with the value of input data, to maintain the ON states and pull up the corresponding data line in case of driving the data line to a "high" level and to fall into OFF states in case of driving the data line to a "low" level. On the other hand, the MOSFETs of the second group are normally in OFF states.
    Type: Grant
    Filed: November 30, 1993
    Date of Patent: August 12, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Tatsumi Yamauchi, Masahiro Iwamura, Kazutaka Mori
  • Patent number: 5654931
    Abstract: A semiconductor integrated circuit device is divided into a plurality of blocks, which are individually equipped with signal generate units such that the signal generate units are distributed in the semiconductor integrated circuit device. The semiconductor integrated circuit device is preferably constructed to generate the pulse signal by the pulse generate units which are provided for the individual blocks, after all initial logic operations on the data and control signals have been taken. Thanks to this construction, an SRAM, for example, can have its write recovery time minimized to 0 so that it can achieve high-speed operations. Moreover, since predecoders are provided for the individual blocks, the wiring line number and area in the chip can be reduced to improve the degree of integration of the semiconductor integrated circuit device. Still moreover, signal delay and skew can be reduced in the chip so that high-speed can be achieved.
    Type: Grant
    Filed: March 16, 1994
    Date of Patent: August 5, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Akihiro Tamba, Masahiro Iwamura, Yutaka Kobayashi, Kinya Mitsumoto, Tatsumi Yamauchi, Shuko Yamauchi, Takashi Akioka
  • Patent number: 5646897
    Abstract: A logic circuit is provided for a memory device which can be operated at a high speed with a lower voltage power source level than conventional devices. This logic circuit can be used in a multi-bit test circuit executing the wired-OR-logic operation of complementary logic signals from a plurality of pre-sense amplifiers, receiving the output of the wired-OR-logic operation by an emitter follower using a bipolar transistor, and outputting an AND signal of the complementary logic signals by a level comparing circuit. A sense amplifier is also provided for executing the wired-OR-logic operation of complementary logic signals from a plurality of pre-sense amplifiers, raising the level of the output of the wired-OR-logic operation by a level shift circuit having a semiconductor element for applying an inverse bias potential to an input signal, executing the wired-OR-operation of the shifted up output and outputs from other blocks, and receiving and amplifying the output of the wired-OR-logic operation.
    Type: Grant
    Filed: April 21, 1995
    Date of Patent: July 8, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Seigou Yukutake, Masahiro Iwamura, Kinya Mitsumoto, Takashi Akioka, Noboru Akiyama
  • Patent number: 5644548
    Abstract: A dynamic random access memory device is provided having a dynamic memory cell, a word line coupled to the dynamic memory cell, a data line coupled to the dynamic memory cell, a precharge circuit coupled to the data line, a word driver coupled to the word line and a decoder coupled to the word driver. A plurality of address lines coupled to the decoder. The decoder has a first logic circuit whose inputs are connected to the plurality of address lines. The decoder also has a latch circuit whose input is connected to an output of the first logic circuit and whose output is connected to the word line.
    Type: Grant
    Filed: August 27, 1996
    Date of Patent: July 1, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Goro Kitsukawa, Takao Watanabe, Ryoichi Hori, Noriyuki Honma, Kunihiko Yamaguchi, Kiyoo Ito, Masahiro Iwamura, Ikuro Masuda
  • Patent number: 5640547
    Abstract: An information processing system having an original clock oscillator for delivering at least one original clock signal K defined as a first clock signal and a plurality of information processing units supplied with the original clock signal K, wherein each information processing unit comprises clock generating means for generating at least one second clock signal K.sub.1 which is phase-locked with the original clock signal K and which has a predetermined duty cycle and a logic device whose operation timing is controlled by the second clock signal K.sub.1, and the operation timing of an interface provided between at least one pair of logic devices is synchronously controlled by the clock signal K.sub.1.
    Type: Grant
    Filed: July 26, 1994
    Date of Patent: June 17, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Hotta, Kozaburo Kurita, Masahiro Iwamura, Hideo Maejima, Shigeya Tanaka, Tadaaki Bandoh, Yasuhiro Nakatsuka, Kazuo Kato, Sin-ichi Sinoda
  • Patent number: 5619151
    Abstract: A semiconductor memory device which includes at least one of (1) an input buffer circuit which generates internal address signals in response to an incoming address; (2) a decoder circuit formed of plural logic gates each of which is composed of the combination of MOS and bipolar circuitry; (3) a sense amplifier circuit including a multiemitter transistor; (4) a signal or address transition detector circuit which includes input circuits each receiving, for example, an address signal of a voltage amplitude and outputting a current amplitude signal in response to a change in level of the address signal, and a detector circuit connected thereto which has a cascode amplifier arranged such that it receives current amplitude signals at an input thereof and in which the cascode amplifier input is maintained at a substantially constant voltage, in which the detection circuit detects a transition of one or more of the current amplitude signals and, in response thereto, generates an ATD signal of a voltage amplitude; a
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: April 8, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Akioka, Masahiro Iwamura, Atsushi Hiraishi, Yuji Yokoyama, Nozomu Matsuzaki, Tatsumi Yamauchi, Yutaka Kobayashi, Nobuyuki Gotou, Akira ide, Masahiro Yamamura, Hideaki Uchida
  • Patent number: 5600268
    Abstract: A high-speed operation, low-power consumption gate circuit structure comprises a combination of complementary field-effect-transistors and bipolar transistors and discharge means for discharging accumulated charges from these transistors when the field-effect-transistors and bipolar transistors are turned off.
    Type: Grant
    Filed: September 30, 1994
    Date of Patent: February 4, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Ikuro Masuda, Kazuo Kato, Takao Sasayama, Yoji Nishio, Shigeo Kuboki, Masahiro Iwamura
  • Patent number: 5590361
    Abstract: An extra large number-of-input complex logic circuit, employed inside a microprocessor for performing a large number of controls and arithmetic operations, is constructed utilizing N(N.gtoreq.2) number of a unit logic circuit each comprising M(M.gtoreq.1) input CMOS logic circuits and one bipolar transistor, whereby respective outputs are integrated to produce one output in response to M.times.N number input signals to provide a high speed, high density integration and low power consumption microprocessor.
    Type: Grant
    Filed: December 23, 1994
    Date of Patent: December 31, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Iwamura, Tatsumi Yamauchi, Shigeya Tanaka, Kazutaka Mori
  • Patent number: 5583814
    Abstract: An arrangement is provided for the input level of an output buffer from fluctuating when a memory device goes from an active state to an inactive state. To achieve this, a level holding circuit is provided at a point connecting an output of a sense circuit for amplifying a signal read from a memory array to an input of an output buffer. The level holding circuit is constituted so that, when the sense circuit goes from an active state to an inactive state, the level holding circuit holds an input level of the output buffer at a time immediately before the sense circuit goes inactive.
    Type: Grant
    Filed: June 14, 1994
    Date of Patent: December 10, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Iwamura, Yutaka Kobayashi, Kei Kato
  • Patent number: 5544125
    Abstract: An arrangement which is particularly effective for decoders in semiconductor memory circuits which use, for example, common NMOS to receive one input for a plurality of logic decoder gates is provided includes a plurality of logic gates each having a first input terminal for respectively receiving first input signals, and each being coupled to a common node. In one embodiment, first and second switching elements are also coupled to the common node. The first and second switching elements are both coupled to a second input terminal for receiving a second input signal which is common to the plurality of logic gates, and both operate complementary to one another in response to the second input signal. An improved read/write arrangement is also provided for such semiconductor memory circuits which includes circuitry to prevent connection of a common read line to the data lines during the writing operation. This enhances the writing speed by removing the load of the common read line during writing.
    Type: Grant
    Filed: February 6, 1995
    Date of Patent: August 6, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Yuji Yokoyama, Takashi Akioka, Masahiro Iwamura, Atsushi Hiraishi, Yutaka Kobayashi, Tatsumi Yamauchi, Shigeru Takahashi, Nobuyuki Gotou, Akira Ide
  • Patent number: 5542083
    Abstract: An information processing system having an original clock oscillator for delivering at least one original clock signal K defined as a first clock signal and a plurality of information processing units supplied with the original clock signal K, wherein each information processing unit comprises clock generating means for generating at least one second clock signal K.sub.1 which is phase-locked with the original clock signal K and which has a predetermined duty cycle and a logic device whose operation timing is controllled by the second clock signal K.sub.1, and the operation timing of an interface provided between at least one pair of logic devices is synchronously controlled by the clock signal K.sub.1.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: July 30, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Hotta, Kozaburo Kurita, Masahiro Iwamura, Hideo Maejima, Shigeya Tanaka, Tadaaki Bandoh, Yasuhiro Nakatsuka, Kazuo Kato, Sin-ichi Sinoda
  • Patent number: 5539686
    Abstract: A carry propagating device, provided on a single substrate, is constituted by groups of first and second MOS transistors, a third MOS transistor, a bipolar transistor and first and second impedance elements. An output of the carry propagating device is provided at the collector of the bipolar transistor and is connected to a first power supply terminal through the first impedance element, the emitter is connected to a second power supply terminal through the second impedance element, and the base is connected to a fixed potential source. The first MOS transistors are connected in series between the emitter of the bipolar transistor and the second power supply terminal through the third MOS transistor controlled by a carry signal.
    Type: Grant
    Filed: September 30, 1994
    Date of Patent: July 23, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Fumio Murabayashi, Takashi Hotta, Masahiro Iwamura, Akiyoshi Osumi
  • Patent number: 5523713
    Abstract: A multiplex circuit is disclosed in which a plurality of bipolar transistors are combined and in which the respective base terminals thereof are used as inputs, thereby to construct an emitter follower type multiplex circuit. In such an emitter follower type multiplex circuit, the multiplexing function of non-selection/selection is effected by controlling the base potential of the respective bipolar transistors by providing a MOS transistor between each base and a high potential of the power source through a resistor and a current drawing circuit. In accordance with such a scheme, when a selection of one input signal is made, the bipolar transistor corresponding thereto is permitted to turn ON on the basis of an input signal supplied to the base terminal thereof.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: June 4, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Seigoh Yukutake, Yutaka Kobayashi, Takashi Akioka, Masahiro Iwamura