Patents by Inventor Shigeki Nozaki
Shigeki Nozaki 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).
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Patent number: 5202849Abstract: A dynamic random access memory comprises a substrate, a transfer transistor provided on the substrate, a memory cell capacitor provided on the substrate in contact with a first diffusion region formed in the substrate, a first conductor pattern provided on the substrate to extend in a first direction as a word line, a first insulator layer provided on the substrate to bury the memory cell capacitor and the first conductor pattern, a first contact hole provided on the first insulator layer to expose a second diffusion region formed in the substrate, a second conductor pattern provided on the first insulator layer to extend in a second direction, passing above the memory cell capacitor and making a contact with the second diffusion region at the first contact hole, a second insulator layer provided on the second conductor pattern, a second contact hole provided on the second insulator layer at a part thereof that locates above the memory cell capacitor to expose the upper major surface of the second conductor pType: GrantFiled: August 18, 1992Date of Patent: April 13, 1993Assignee: Fujitsu LimitedInventor: Shigeki Nozaki
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Patent number: 5119335Abstract: A semiconductor memory device including a pair of bit lines, a memory cell provided between the pair of bit lines, and a potential difference control device connected to the pair of bit lines. The bit lines include a potential difference therebetween when information stored in the memory cell is read out. The potential difference control device has a transistor control for receiving a first control signal and for responding thereto; thereby, increasing the potential difference between the pair of bit lines up to a predetermined level so as to provide a high speed read-operation and to reliably discriminate a "good" or a "no good" reading when subjected to a screening test.Type: GrantFiled: June 5, 1991Date of Patent: June 2, 1992Assignee: Fujitsu LimitedInventor: Shigeki Nozaki
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Patent number: 4970693Abstract: A semiconductor memory device is connected to a power source and includes a reference potential line connected to receive a reference potential from the power source. An input circuit is connected to the reference potential line and receives an external input signal having a logic level defined in reference to the reference potential to be supplied to the source potential line. The output circuit has an external output terminal which is connected to the reference potential line. The output circuit is for generating an output to the external output terminal. An inhibiting circuit inhibits a response to the external input signal of the input circuit for a predetermined period during which the output of the output circuit changes.Type: GrantFiled: February 23, 1990Date of Patent: November 13, 1990Assignee: Fujitsu LimitedInventors: Shigeki Nozaki, Tsuyoshi Ohira, Masaru Satoh, Tomio Nakano, Yoshihiro Takemae
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Patent number: 4771407Abstract: In a semiconductor integrated circuit having first and second power supply lines for receiving a power supply voltage, an external input terminal for receiving an input signal, and a high voltage detection circuit for detecting at the external input terminal a high voltage higher than a predetermined voltage which is higher than the power supply voltage, the high voltage detection circuit comprises an input circuit connected to the external input terminal for generating circuit for generating a reference voltage; and a differential voltage amplifier connected to receive the detection voltage and the reference voltage for amplifying the difference between the detection voltage and the reference voltage, to thereby determine whether the high voltage is applied, the input circuit comprising; a level shift element connected to the external input terminal for providing the detection voltage; an impedance element connected between the level shift element and the second power supply line; and a leak current compensaType: GrantFiled: July 29, 1987Date of Patent: September 13, 1988Assignee: Fujitsu LimitedInventors: Yoshihiro Takemae, Shigeki Nozaki, Masao Nakano, Kimiaki Sato, Hatsuo Miyahara, Nobumi Kodama, Makoto Yanagisawa, Yasuhiro Takada, Satoshi Momozono
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Patent number: 4742486Abstract: In a semiconductor integrated circuit comprising an internal circuit, a device for receiving a chip select signal from the outside, a device for receiving an input signal from the outside, and a voltage detecting circuit for detecting whether or not the potential of the input signal is higher than a reference potential; the voltage detecting circuit comprises a first device for differentially comparing the potential of the input signal with the reference potential and generating an output potential in accordance with the results of the comparison, a second device for detecting a predetermined edge of the chip select signal so as to trigger the first device, and a third device for latching the output potential of the first device to the third device when the first device is triggered by the second device, the internal circuit being switched from a first mode to a second mode, or vice versa, in accordance with the output potential of the third device.Type: GrantFiled: May 8, 1986Date of Patent: May 3, 1988Assignee: Fujitsu LimitedInventors: Yoshihiro Takemae, Shigeki Nozaki, Masao Nakano, Kimiaki Sato, Nobumi Kodama
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Patent number: 4739502Abstract: A clock signal generating circuit for a dynamic type semiconductor memory device including an input voltage level control unit for converting a transistor-transistor-logic (TTL) drive level to a metal-oxide-semiconductor (MOS) drive level during transmission of an address strobe signal; an address buffer control unit for generating an address signal and an inverted address signal in response to a trailing edge of the address strobe signal, a clock signal generating unit for generating a clock signal used for a word line selection and an input signal for a next stage in response to a low level of the address strobe signal, and an inhibiting unit for inhibiting a drive of the word line by the clock signal when the address strobe signal is at high level in the timing of a leading edge of the clock signal.Type: GrantFiled: August 7, 1986Date of Patent: April 19, 1988Assignee: Fujitsu LimitedInventor: Shigeki Nozaki
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Patent number: 4716549Abstract: A semiconductor memory device capable of compensating for variation in a discriminating voltage of a memory cell comprising a memory cell and a gate circuit for coupling the memory cell to a bit line. The device has a precharge circuit for precharging the bit line pair to a predetermined resultant precharge voltage in a reset state. The precharge circuit precharges a bit line pair with the resultant precharge voltage obtained by adding a compensating voltage to a precharge voltage in the reset state. The compensating voltage is adapted to compensate for variation in a memory cell discriminating voltage based on variation in a memory cell voltage caused by capacitive coupling of a word line to a memory capacitor due to a parasitic capacitance of a gate circuit in the active state, and the precharge voltage is adapted to optimize the memory cell discriminating voltage when it is assumed that the parasitic capacitance is not present.Type: GrantFiled: August 29, 1986Date of Patent: December 29, 1987Assignee: Fujitsu LimitedInventors: Masao Nakano, Yoshihiro Takemae, Tomio Nakano, Shigeki Nozaki, Kimiaki Sato, Nobumi Kodama
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Patent number: 4602356Abstract: A semiconductor memory device operates under a so-called address multiplex access method. A row part of the device is enabled by receiving a row address strobe (RAS) signal. A column part of the device is enabled by simultaneously receiving both a column address strobe (CAS) signal and a timing control signal supplied from the row part during its enable state. A column address buffer in the column part is enabled by simultaneously receiving both the CAS signal and a timing control signal. The timing control signal is produced from a circuit when it detects and holds the RAS signal.Type: GrantFiled: December 1, 1982Date of Patent: July 22, 1986Assignee: Fujitsu LimitedInventors: Shigeki Nozaki, Yoshihiro Takemae, Seiji Enomoto
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Patent number: 4583204Abstract: A dynamic semiconductor memory device includes data output lines (D, D), a data output buffer (12), a column enable buffer (9), and an output enable buffer (11) for generating an output enable signal (OE) to enable the transmission of data from the data output lines to the data buffer. The output enable buffer is driven by the clock signals of the column enable buffer. An output disabling circuit (13) is provided to stop the generation of an output enable signal by the output enable buffer when the output enable buffer is not being driven by the column enable buffer. As a result, the data output buffer assumes a high-impedance state when a power supply is turned on.Type: GrantFiled: December 23, 1982Date of Patent: April 15, 1986Assignee: Fujitsu LimitedInventors: Yoshihiro Takemae, Shigeki Nozaki, Tsuyoshi Ohira
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Patent number: 4570088Abstract: A semiconductor device, provided with a buffer, which comprises a first transistor for pulling up the output terminal voltage, a second transistor for pulling down the output terminal voltage, and a charge-pumping circuit for maintaining the output terminal voltage at a level higher than the power source voltage by charge pumping when the output terminal voltage is at a high level. The semiconductor device further comprises a circuit for pulling down the output terminal voltage during the period from when power is supplied to when an input signal is supplied to the buffer.Type: GrantFiled: July 1, 1983Date of Patent: February 11, 1986Assignee: Fujitsu LimitedInventors: Shigeki Nozaki, Tomio Nakano, Katsuhiko Kabashima
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Patent number: 4550289Abstract: A semiconductor integrated circuit (IC) device includes therein a test circuit. The test circuit operates to distinguish the power source level during the testing or ground level occurring at an internal node located inside the semiconductor chip. The test circuit includes a series-connected MIS transistor and an MIS diode. The gate of the MIS transistor is connected to the internal node. The MIS diode is connected to an external input/output (I/O) pin. The level at the internal node, i.e., the power source level or the ground level, can be distinguished by a first voltage level or a second voltage level applied to the external I/O pin, whichever enables a current to be drawn from the external I/O pin.Type: GrantFiled: December 27, 1982Date of Patent: October 29, 1985Assignee: Fujitsu LimitedInventors: Katsuhiko Kabashima, Yoshihiro Takemae, Shigeki Nozaki, Tsuyoshi Ohira, Hatsuo Miyahara, Masakazu Kanai, Seiji Enomoto
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Patent number: 4546457Abstract: A metal-insulator semiconductor dynamic memory device comprising sense amplifiers arrayed on a semiconductor substrate and column decoders. Each of the column decode being provided for a plurality of sense amplifiers and selecting one or more sense amplifiers from the plurality of sense amplifiers, the column decoders being dispersed on both sides of the arrayed sense amplifiers. A plurality of control signal lines which, in order to select the sense amplifiers, control gate elements connected between bit lines connected to the sense amplifiers and data bus lines and which are disposed on both sides of the arrayed sense amplifiers. Conducting lines are also disposed between the sense amplifiers and deliver signals from the control signal lines, for selecting sense amplifiers to the gate elements on the opposite side of the control signal lines with regard to the arrayed sense amplifiers.Type: GrantFiled: November 5, 1982Date of Patent: October 8, 1985Assignee: Fujitsu LimitedInventors: Shigeki Nozaki, Yoshihiro Takemae
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Patent number: 4535423Abstract: A semiconductor memory device which includes a plurality of memory cells each having a capacitor, and peripheral circuits of the memory cells, integrated on a semiconductor substrate. Each capacitor has a storage electrode and an electrode opposite to the storage electrode, the opposite electrode being connected to a ground line, wherein, the ground line connected to the opposite electrode of each capacitor is separated from the other ground lines connected to the peripheral circuits. All of the ground lines are connected to a common portion having an impedance lower than the impedance of each ground line, whereby data stored in the capacitors is prevented from being destroyed.Type: GrantFiled: December 7, 1982Date of Patent: August 13, 1985Assignee: Fujitsu LimitedInventors: Shigeki Nozaki, Hatsuo Miyahara
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Patent number: 4511997Abstract: A metal-insulator semiconductor dynamic memory device including sense amplifiers arrayed on a semiconductor substrate and divided into a plurality of sense amplifier groups. Column decoders are provided, one decoder for each sense amplifier group, each sense amplifier group being selected by the column decoder. One or more control signal lines for simultaneously selecting the output signals of at least two sense amplifiers in the sense amplifier group selected by the column decoder, a plurality of data buses for transferring the output signals of at least two sense amplifiers selected by one or more control signal lines, are included in the memory device. All of the sense amplifiers have the control signal lines and the data buses in common.Type: GrantFiled: November 5, 1982Date of Patent: April 16, 1985Assignee: Fujitsu LimitedInventors: Shigeki Nozaki, Yoshihiro Takemae, Tomio Nakano
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Patent number: 4496850Abstract: A semiconductor circuit for driving a clock signal line comprising a first circuit for pulling up the potential of the clock signal line to the source voltage and a second circuit for pulling down the potential of the clock signal line to a lower voltage. A capacitor is connected to the clock signal line for receiving a potential push signal and pushing the potential of the clock signal line higher than the source voltage. The capacitor performs the function of capacitance only after the potential of the clock signal line is raised to the source voltage. The operational speed of a dynamic memory device associated with the semiconductor device is then enhanced.Type: GrantFiled: February 10, 1982Date of Patent: January 29, 1985Assignee: Fujitsu LimitedInventors: Yoshihiro Takemae, Shigeki Nozaki, Katsuhiko Kabashima, Seiji Enomoto
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Patent number: 4482825Abstract: In a semiconductor device having a signal line on which a voltage higher than the voltage supply is generated, a conductive layer following the potential variance of the voltage supply is positioned under an insulating film directly below the signal line in order to make the level of the signal line follow the potential variance of the voltage supply.Type: GrantFiled: December 2, 1981Date of Patent: November 13, 1984Assignee: Fujitsu LimitedInventors: Shigeki Nozaki, Yoshihiro Takemae, Katsuhiko Kabashima, Seiji Enomoto
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Patent number: 4458337Abstract: A buffer circuit comprises a flip-flop which is receives an external input via a first input circuit and a reference voltage via a second input circuit. Internal complementary outputs are then produced via an output circuit. The flip-flop cooperates with at least one level setting device by way of a second input circuit. The level setting device functions to produce a voltage level to deactivate the second input circuit during activation of the flip-flop.Type: GrantFiled: March 3, 1982Date of Patent: July 3, 1984Assignee: Fujitsu LimitedInventors: Yoshihiro Takemae, Shigeki Nozaki, Tsutomu Mezawa, Katsuhiko Kabashima, Seiji Enomoto
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Patent number: 4451908Abstract: An address buffer for a dynamic memory includes a flip-flop. The flip-flop is coupled at its one input/output terminal with both a first input circuit and a third input circuit connected in parallel with each other and at its other input/output terminal with a second input circuit. The second input circuit receives a reference voltage and is activated by an external address timing clock during a normal operation mode. The first input circuit is also activated by the external address timing clock, but receives an external address. The third input circuit receives an internal refresh address and is activated by an internal refresh address. The address buffer cooperates with a switcher which produces the internal refresh address timing clock and the external address timing clock, alternatively, by switching a basic timing clock generated by an address drive clock generator.Type: GrantFiled: March 3, 1982Date of Patent: May 29, 1984Assignee: Fujitsu LimitedInventors: Yoshihiro Takemae, Shigeki Nozaki, Katsuhiko Kabashima, Seiji Enomoto, Tsutomu Mezawa
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Patent number: 4447745Abstract: A semiconductor circuit used as a buffer circuit having an input stage circuit for receiving an input clock signal and an inverted input clock signal, a bootstrap circuit including a transistor for receiving the output of the input stage circuit and for maintaining the gate voltage of the transistor at a high level during the standby period, and an output circuit, including a transistor which is switched on and off by the output of the bootstrap circuit, for generating an output clock signal; the semiconductor circuit further comprising a current leak circuit for maintaining, during the standby period, the voltage of a point in the semiconductor circuit which is charged during the standby period at the value corresponding to the voltage of the power source, whereby the delay of the output clock signal, caused of the fluctuation by the voltage of the power supply during the standby period, is improved and then the high speed access time in the dynamic memory is carried out.Type: GrantFiled: November 18, 1981Date of Patent: May 8, 1984Assignee: Fujitsu LimitedInventors: Yoshihiro Takemae, Seiji Enomoto, Shigeki Nozaki, Tsutomu Mezawa, Katsuhiko Kabashima
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Patent number: 4430581Abstract: A semiconductor circuit consisting of a dynamic-type circuit and a bias-voltage generating circuit. The bias-voltage generating circuit is comprised of a first bias-voltage generator and a second bias-voltage generator. The first generator absorbs a variable substrate current, the magnitude of which is proportional to the operating frequency of the dynamic-type circuit, while the second generator absorbs a substrate current, the magnitude of which is not proportional to the operating frequency of the dynamic-type circuit. Alternately, both portions of the substrate current may be absorbed via the same circuitry.Type: GrantFiled: May 13, 1981Date of Patent: February 7, 1984Assignee: Fujitsu LimitedInventors: Jun-ichi Mogi, Kiyoshi Miyasaka, Seiji Enomoto, Shigeki Nozaki