Patents by Inventor Hironori Akamatsu

Hironori Akamatsu 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: 5699300
    Abstract: A semiconductor memory device comprising memory cells arranged in a matrix with plural pairs of bit lines to be column addressed and connected to sense amplifiers, and word lines to be row addressed and divided into divisional word lines. Output signals of sense amplifiers selected by the column addressing are transferred to respective data lines. The divisional word lines are time-sequentially activated corresponding to the row addressing with the activated states of any two sequential divisional word lines overlapped for a fractional time of the full activation time. The sense amplifiers are grouped into plural groups with respective common column addresses. Each group of sense amplifiers have their outputs to be applied to respective data lines connected to a serial/parallel converter.
    Type: Grant
    Filed: November 16, 1994
    Date of Patent: December 16, 1997
    Inventors: Hironori Akamatsu, Tsuyoshi Shiragasawa, Junko Matsushima, Hisakazu Kotani
  • Patent number: 5680366
    Abstract: In a driver circuit for driving a pair of data lines, the amplitude of a differential input signal is reduced from 2.5 V to 0.6 V, which is smaller than a conventional lower-limit source voltage (approximately 1.5 V). The amplitude of the differential signal transmitted through the pair of data lines is amplified to 2.5 V by an amplifying circuit and the resulting signal is then latched by a latch circuit. After the latching by the latch circuit, the operation of the amplifying circuit is halted. The driver circuit is constituted solely by a plurality of NMOS transistors so as not to increase a leakage current flowing in the off state. Here, the threshold voltage of the NMOS transistor positioned on the ground side is reduced to a conventional lower-limit value (0.3 V to 0.6 V), while the threshold voltage of the NMOS transistor on the power-source side to a value lower than the above lower-limit value (0 V to 0.3 V), thereby enhancing a driving force of the NMOS transistor on the power-source side.
    Type: Grant
    Filed: December 15, 1995
    Date of Patent: October 21, 1997
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hisakazu Kotani, Hironori Akamatsu, Toshio Yamada, Akihiro Sawada, Hirohito Kikukawa, Masashi Agata, Shunichi Iwanari
  • Patent number: 5672995
    Abstract: There are provided a MIS transistor having a substrate portion, a gate, a source, and a drain, a back-bias generator to be applied to the substrate portion of the MIS transistor, and a resistor interposed between the substrate portion of the MIS transistor and the back-bias generator so that the potential between the both ends thereof changes in a range from one value in the active mode to the other value in the standby mode of the MIS transistor. In the MIS transistor, the back bias is self-regulated so that it approaches to zero in the active mode, while it moves away from zero in the standby mode. Consequently, the threshold voltage is reduced in the active mode due to the back bias approaching to zero, so that higher-speed operation is performed. On the other hand, off-state leakage is suppressed in the standby mode due to the back bias moving away from zero. Thus, it becomes possible to constitute a semiconductor apparatus which operates at high speed with low power consumption.
    Type: Grant
    Filed: November 14, 1994
    Date of Patent: September 30, 1997
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Junji Hirase, Hironori Akamatsu, Susumu Akamatsu, Takashi Hori
  • Patent number: 5642323
    Abstract: In a driver circuit for driving a pair of data lines, the amplitude of a differential input signal is reduced from 2.5 V to 0.6 V, which is smaller than a conventional lower-limit source voltage (approximately 1.5 V). The amplitude of the differential signal transmitted through the pair of data lines is amplified to 2.5 V by an amplifying circuit and the resulting signal is then latched by a latch circuit. After the latching by the latch circuit, the operation of the amplifying circuit is halted. The driver circuit is constituted solely by a plurality of NMOS transistors so as not to increase a leakage current flowing in the off state. Here, the threshold voltage of the NMOS transistor positioned on the ground side is reduced to a conventional lower-limit value (0.3 V to 0.6 V), while the threshold voltage of the NMOS transistor on the power-source side to a value lower than the above lower-limit value (0 V to 0.3 V), thereby enhancing a driving force of the NMOS transistor on the power-source side.
    Type: Grant
    Filed: December 15, 1995
    Date of Patent: June 24, 1997
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hisakazu Kotani, Hironori Akamatsu, Ichiro Nakao, Toshio Yamada, Akihiro Sawada, Hirohito Kikukawa, Masashi Agata, Shunichi Iwanari
  • Patent number: 5555527
    Abstract: A memory array divided into a plurality of sub-memory-arrays is disposed on a chip so that, if a specified sub-memory-array is selected by a sub-memory-array selecting circuit, a normal read/write operation is performed with respect to the sub-memory-array based on an address indicated by a group of external address signals. At the same time, a clock generator for self-refresh mounted on a chip generates a word-line basic clock for self-refresh and a word-line basic clock for refresh, thereby selecting the word lines in the sub-memory-arrays which have not been selected. Prior to a predetermined time at which the sub-memory-array subjected to a refresh operation is subsequently selected, a refresh halt signal is outputted so as to forcibly halt the refresh operation, thereby preventing insufficient recharging of a memory cell. Each of the plurality of sub-memory-arrays stores, of sequential sets of image data, data on one frame or one field.
    Type: Grant
    Filed: December 14, 1994
    Date of Patent: September 10, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hisakazu Kotani, Hironori Akamatsu, Tsutomu Fujita
  • Patent number: 5546346
    Abstract: In a synchronous DRAM required to be capable of performing high-speed consecutive operations in synchronism with a clock signal, a DBI-line pair is connected between a DQ-line pair and an RDB-line pair, and pipeline operation whose single cycle time is divided into four periods is employed.
    Type: Grant
    Filed: December 6, 1994
    Date of Patent: August 13, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masashi Agata, Kazuhiro Matsuyama, Hironori Akamatsu, Hirohito Kikukawa, Akihiro Sawada, Shunichi Iwanari
  • Patent number: 5515334
    Abstract: In a driver circuit for driving a pair of data lines, the amplitude of a differential input signal is reduced from 2.5 V to 0.6 V, which is smaller than a conventional lower-limit source voltage (approximately 1.5 V). The amplitude of the differential signal transmitted through the pair of data lines is amplified to 2.5 V by an amplifying circuit and the resulting signal is then latched by a latch circuit. After the latching by the latch circuit, the operation of the amplifying circuit is halted. The driver circuit is constituted solely by a plurality of NMOS transistors so as not to increase a leakage current flowing in the off state. Here, the threshold voltage of the NMOS transistor positioned on the ground side is reduced to a conventional lower-limit value (0.3 V to 0.6 V), while the threshold voltage of the NMOS transistor on the power-source side to a value lower than the above lower-limit value (0 V to 0.3 V), thereby enhancing a driving force of the NMOS transistor on the power-source side.
    Type: Grant
    Filed: June 15, 1994
    Date of Patent: May 7, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hisakazu Kotani, Hironori Akamatsu, Ichiro Nakao, Toshio Yamada, Akihiro Sawada, Hirohito Kikukawa, Masashi Agata, Shunichi Iwanari
  • Patent number: 5508963
    Abstract: N-piece redundant address comparing circuits are individually composed of impedance converting circuits, so that information using redundancy is transmitted as an impedance value. Consequently, even though the N becomes larger as the capacity of a memory becomes larger, a signal line having large capacitance and the node of a redundant judging circuit are not charged or discharged. A high-speed operation can be realized without being affected by the capacitance of the signal line or by the capacitance of the node of the redundant judging circuit.
    Type: Grant
    Filed: March 11, 1994
    Date of Patent: April 16, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Akihiro Sawada, Hiroyuki Yamauchi, Hironori Akamatsu, Shunichi Iwanari, Masashi Agata, Hirohito Kikukawa, Hisakazu Kotani
  • Patent number: 5426601
    Abstract: An external power supply voltage V.sub.CC is applied to a peripheral circuit as a first internal power supply voltage V.sub.PERI. A power supply voltage control circuit outputs a voltage control signal V.sub.SIG of a high logic level if V.sub.CC is not greater than a low limit voltage V.sub.0L in a voltage range specified by VCC recommended operating conditions, otherwise it outputs V.sub.SIG of a low logic level. A power supply circuit applies a second internal power supply voltage V.sub.W and a third internal power supply voltage V.sub.WORD to a memory cell section. V.sub.W is equal to V.sub.PERI if V.sub.SIG is HIGH, while on the other hand V.sub.W is a voltage as a result of boosting V.sub.PERI. V.sub.WORD is a voltage as a result of boosting VW to a further extent. A row decoder sends out V.sub.W onto an enable signal line of a row of sense amplifiers, and V.sub.WORD onto a word line of a memory cell array so that V.sub.W becomes a high-logic-level data write voltage to a memory cell.
    Type: Grant
    Filed: January 24, 1994
    Date of Patent: June 20, 1995
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masashi Agata, Hironori Akamatsu, Hirohito Kikukawa, Akihiro Sawada, Shunichi Iwanari
  • Patent number: 5293339
    Abstract: A semiconductor integrated circuit contains a plurality of programmable circuits each including a plurality of fuses and a first transistor which has a gate subjected to an address decoded signal, a drain connected to first ends of the fuses, and a source connected to a common precharge node. The address decoded signal results from decoding a first portion of an address signal for access to memory cells. The sources of the first transistors in the respective programmable circuits are connected to the common precharge node. A plurality of second transistors have gates subjected to a second portion of the address signal, sources connected to a first power supply line, and drains connected to second ends of the fuses in each of the programmable circuits respectively. The second portion of the address signal differs from the first portion of the address signal.
    Type: Grant
    Filed: April 3, 1992
    Date of Patent: March 8, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Toshikazu Suzuki, Hisakazu Kotani, Hironori Akamatsu
  • Patent number: 5251177
    Abstract: An improved arrangement for refreshing a semiconductor memory device comprising a plurality of memory blocks is disclosed. In the memory device, word lines of all memory blocks are commonly controlled by one controller. One of the memory blocks is selected to be subject to the write/read operation. The refresh is performed in the remaining memory blocks while the selected memory block is written or read. The period of time required for the refresh can be decreased.
    Type: Grant
    Filed: November 26, 1991
    Date of Patent: October 5, 1993
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hironori Akamatsu, Akinori Shibayama, Hisakazu Kotani, Junko Matsushima
  • Patent number: 5150327
    Abstract: A semiconductor memory includes a writing circuit for dividing data continuously supplied to a serial data input circuit into a plurality of bits, a serial data output circuit for continuously providing data read out a plurality of bits a a time by a reading circuit, a memory cell array including a column decoder and a row decoder, column and row address buffers for instructing addresses for a plurality of bits at a time to the respective column and row decoders, an address generator, and a circuit provided between the address generator and column decoder and including a read column address generator, a write column address generator and a column address control circuit for switching read and write column address generated from the read and write column address generators, wherein address identity data are simultaneously inputted and outputted through switching of internal column addresses for reading and writing.
    Type: Grant
    Filed: August 29, 1991
    Date of Patent: September 22, 1992
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Junko Matsushima, Hironori Akamatsu
  • Patent number: 4975932
    Abstract: Through the step number control transfer gate activated by the step number control signal, the input data is sent into a specific transfer step of the shift register, and the data transferred from the specific transfer step is delivered from the output step. By selecting an arbitrary step number control transfer gate, the input transfer step is varied without changing the output step to change to an arbitrary data delay length. Therefore, only by increasing the driving capacity of the driver of the input data, a shift register short in delay time, small in increase of integration area, and low in power consumption will be obtained.
    Type: Grant
    Filed: December 27, 1988
    Date of Patent: December 4, 1990
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Junko Matsushima, Tsuoshi Shiragasawa, Hironori Akamatsu