Patents by Inventor Daisaburo Takashima

Daisaburo Takashima 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).

  • Publication number: 20100060346
    Abstract: According to an aspect of the present invention, there is provided a reference voltage generation circuit including: a first transistor having a first gate, a first source and a first drain; a second transistor having a second gate connected to the first gate, a second source connected to the first source and a second drain; a first diode connected between a ground and a V? node; a first resistor connected between the V? node and the first drain; a second diode and a second resistor connected between the ground and a V+ node; a third resistor connected between the V+ node and the first drain; an operational amplifier including input ports connected to the V+ node and the V? node and an output port connected to the first gate and the second gate; and a fourth resistor connected between the ground and the second drain.
    Type: Application
    Filed: November 13, 2009
    Publication date: March 11, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Ryu OGIWARA, Daisaburo TAKASHIMA
  • Publication number: 20100054064
    Abstract: A semiconductor memory apparatus includes: a bit line; a word line; a local bit line; a first switch unit provided between the local bit line and the bit; a memory cell connected to the bit line and the word line; a memory cell array including the memory cell; a first sense circuit connected to the bit line and configured to amplify a signal read out from the memory cell; and a second sense circuit connected to the local bit lines and configured to amplify a signal amplified by the first sense circuit, wherein the first switch unit disconnects the local bit line from the bit line when the first sense circuit amplifies the signal, and connects the local bit line to the bit line when the second sense circuit amplifies the signal amplified by the first sense circuit.
    Type: Application
    Filed: September 2, 2009
    Publication date: March 4, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tadashi MIYAKAWA, Daisaburo TAKASHIMA
  • Publication number: 20100020587
    Abstract: A ferroelectric memory is provided with a voltage generating circuit configured to generate prescribed driving potential, a driving interconnection to which the driving potential is applied, a plurality of memory cells connected to the driving interconnections and an internal voltage comparison circuit configured to compare inputted potential and to output results thereof. A plurality of voltage monitoring interconnections are provided to connect between a portion of the driving interconnection disposed at a position distant from the voltage generating circuit on the substrate and the internal voltage comparison circuit. The internal voltage comparison circuit compares potential inputted through the voltage monitoring interconnection with the driving potential.
    Type: Application
    Filed: July 20, 2009
    Publication date: January 28, 2010
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Sumiko DOUMAE, Daisaburo Takashima
  • Publication number: 20100020589
    Abstract: The sense amplifier detects and amplifies a signal read via bit lines from the ferroelectric capacitor of the memory cell. The dummy capacitor provides a reference voltage to bit lines. The dummy capacitor includes a first dummy capacitor and a second dummy capacitor. The first dummy capacitor is provided with a first dummy plate potential at one end to set the reference voltage to a certain potential. The other end is connected to the bit line. The second dummy capacitor is provided with a second dummy plate potential at one end to fine-tune the reference voltage from the certain potential. The other end thereof is connected to the bit line.
    Type: Application
    Filed: July 28, 2009
    Publication date: January 28, 2010
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Sumiko DOUMAE, Daisaburo TAKASHIMA
  • Publication number: 20100020627
    Abstract: A memory includes a cell array; bit lines; word lines; sense amplifiers; first determination transistors receiving information data and making a connection between a first voltage source and a first determination node be in a conductive or a non-conductive state based on a logic value of the information data; second determination transistors receiving the information data detected by the sense amplifiers and making a connection between the first voltage source and a second determination node be in a conductive or a non-conductive state based on the logic value of the information data; a second voltage source charging the first and the second determination nodes; and a determination unit detecting potentials of the first determination node and the second determination node when a logic of the information data is inverted logically to determine maximum and minimum values of potential of the information data.
    Type: Application
    Filed: July 21, 2009
    Publication date: January 28, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tadashi Miyakawa, Daisaburo Takashima
  • Publication number: 20100014341
    Abstract: A memory includes word lines; plate lines; first to eighth bit lines; cell transistors; ferroelectric capacitor connected in parallel with cell transistors; sense amplifiers, wherein cell transistors and ferroelectric capacitors configure cells, the cells are connected in series to configure first to eighth cell blocks, the cell blocks are connected to the same word lines, first ends of the cell blocks are respectively connected to the bit lines, second ends of the cell blocks are respectively connected to the different plate lines, one of the first to the fourth bit lines and one of the fifth to the eighth bit lines are configured to be selectively connected to the sense amplifier during an operation, numbers of the cells connected in series between the bit lines and the plate lines are different in the first to the fourth cell blocks, and are different in the fifth to the eighth cell blocks.
    Type: Application
    Filed: July 14, 2009
    Publication date: January 21, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Daisaburo Takashima
  • Patent number: 7649763
    Abstract: According to an aspect of the invention, there is provided a nonvolatile ferroelectric memory, including a ferroelectric capacitor composed of a ferroelectric film sandwiched by capacitor electrodes made of a conductive material, a cell capacitor block stacked a plurality of the capacitor electrodes and the ferroelectric film of the ferroelectric capacitor perpendicular to a main surface of a silicon substrate in layer, a cell transistor having a drain electrode and a source electrode, the drain electrode and the source electrode are electrically connected to the ferroelectric capacitor in parallel, a memory cell composed of the ferroelectric capacitor and the cell transistor, a cell block having the plurality of memory cells electrically connected in series, the drain electrode and the source electrode being as a terminals, a word line, a bit line connected to one end of the cell block, the bit line being arranged along orthogonal direction to the word line and a plate line connected to the other end of the
    Type: Grant
    Filed: March 22, 2007
    Date of Patent: January 19, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Daisaburo Takashima
  • Publication number: 20100011260
    Abstract: To provide a memory system which determines a memory state such as an exhaustion level and allows a memory to be efficiently used. The memory system includes a NAND type flash memory 1 in which data can be electrically written/erased, a nonvolatile memory 2 which counts the number of erase operations of the NAND type flash memory 1 and retains the number of erase operations and a maximum number of erase operations, and a controller 3 which has a connection interface 31 to be given a self-diagnosis command from a computer 4, and retrieves the number of erase operations and the maximum number of erase operations from the nonvolatile memory 2 based on the self-diagnosis command and outputs the number of erase operations and the maximum number of erase operations to the computer 4 through the connection interface 31.
    Type: Application
    Filed: November 28, 2007
    Publication date: January 14, 2010
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yasushi Nagadomi, Daisaburo Takashima, Kosuke Hatsuda, Shinichi Kanno
  • Publication number: 20100002493
    Abstract: A precharge circuit precharges a bit line paired with the bit line to which the selected one of the memory cells is connected, by applying to the former bit line an external reference voltage for comparison with a voltage in the bit line caused by selection of the memory cell. A precharge assist circuit, which is connected to the former bit line in parallel with the precharge circuit, charges the bit line to a predetermined potential by using a power supply voltage. A sense amplifier, which is connected to the pair of bit lines, senses and amplifies a potential of a bit line that is connected to a memory cell selected by word lines.
    Type: Application
    Filed: July 3, 2009
    Publication date: January 7, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tadashi Miyakawa, Daisaburo Takashima
  • Patent number: 7633330
    Abstract: According to an aspect of the present invention, there is provided a reference voltage generation circuit including: a first transistor having a first gate, a first source and a first drain; a second transistor having a second gate connected to the first gate, a second source connected to the first source and a second drain; a first diode connected between a ground and a V? node; a first resistor connected between the V? node and the first drain; a second diode and a second resistor connected between the ground and a V+ node; a third resistor connected between the V+ node and the first drain; an operational amplifier including input ports connected to the V+ node and the V? node and an output port connected to the first gate and the second gate; and a fourth resistor connected between the ground and the second drain.
    Type: Grant
    Filed: November 5, 2007
    Date of Patent: December 15, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryu Ogiwara, Daisaburo Takashima
  • Patent number: 7609099
    Abstract: A circuit for detecting a power-on voltage of power supply encompasses a voltage divider connected between a first power supply and a second power supply, the potential of the second power supply is lower than the potential of the first power supply, and a detecting circuit connected between the first power supply and the second power supply. The voltage divider includes a series circuit encompassing a diode, a first dividing resistor connected to the diode and a second dividing resistor connected between the first dividing resistor and the second power supply. The detecting circuit includes a pMOS transistor whose gate electrode is connected to a connection node between the first dividing resistor and the second dividing resistor, a source resistor connected between the first power supply and the source electrode of the pMOS transistor and a drain resistor connected to the drain electrode of the pMOS transistor and the second power supply.
    Type: Grant
    Filed: November 9, 2006
    Date of Patent: October 27, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryu Ogiwara, Daisaburo Takashima
  • Publication number: 20090256542
    Abstract: A power supply circuit has a constant voltage circuit, a first MOS transistor, a second MOS transistor, a third MOS transistor, a first voltage dividing circuit that outputs a first divided voltage obtained by dividing the voltage of the output terminal by a first voltage dividing ratio, and a first differential amplifier circuit which is fed with a reference voltage and the first divided voltage and has an output connected to a gate of the second MOS transistor. The first differential amplifier circuit outputs a signal to turn on the second MOS transistor when the first divided voltage is higher than the reference voltage, and the first differential amplifier circuit outputs a signal to turn off the second MOS transistor when the first divided voltage is lower than the reference voltage.
    Type: Application
    Filed: March 16, 2009
    Publication date: October 15, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hidehiro SHIGA, Shinichiro Shiratake, Daisaburo Takashima
  • Publication number: 20090231902
    Abstract: A memory includes ferroelectric capacitors; cell transistors each including a drain connected to one electrode of each ferroelectric capacitor, and a gate connected to the word line; and memory cell blocks each including a reset transistor, a block selection transistor, and memory cells including the ferroelectric capacitors and the cell transistors, wherein sources of the cell transistors are connected to the plate lines, the other electrode of the ferroelectric capacitor is connected to one of the sub-bit lines, a source and a drain of the block selection transistor are connected to one of the sub-bit lines and one of the bit lines, a source of the reset transistor is connected to one of the plate lines or a fixed potential, and a drain of the reset transistor in each memory cell block is connected to one of the sub-bit lines, and the memory cell blocks configure a memory cell array.
    Type: Application
    Filed: March 10, 2009
    Publication date: September 17, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Daisaburo Takashima
  • Publication number: 20090235015
    Abstract: A memory system includes a non-volatile memory constituted by blocks each of which is an erase unit constituted by pages each of which is a write/read unit constituted by memory cells; a random access memory temporarily storing data which is written in or read from the non-volatile memory; and a controller controlling the non-volatile memory and the random access memory, wherein the non-volatile memory includes a main memory area in which the block is divided into first management units respectively specified by logical addresses and a cache area in which the block is divided into second management units respectively specified by logical addresses, a data capacity of one of the second management units is smaller than that of one of the first management units, and the controller changes number of the blocks in the main memory area and number of the blocks in the cache area in the non-volatile memory.
    Type: Application
    Filed: March 10, 2009
    Publication date: September 17, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kosuke Hatsuda, Daisaburo Takashima, Yasushi Nagadomi
  • Publication number: 20090231903
    Abstract: A driver circuit and a precharge circuit apply, in a test mode, a fixed potential to a bit-line, while applying a second plate-line voltage to a plate-line. Then, the bit-line is switched from a first bit-line precharge potential to a floating state, and the plate-line voltage is raised from the second plate-line voltage to a plate-line voltage.
    Type: Application
    Filed: March 13, 2009
    Publication date: September 17, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Ryu OGIWARA, Daisaburo TAKASHIMA
  • Patent number: 7589513
    Abstract: A reference voltage generator circuit comprises a first current path and a second current path. The first current path is formed between an input terminal supplied with a first reference voltage and an output terminal and including a first diode and a first resistor serially connected from the input terminal. The second current path is formed between the input terminal and the output terminal and including a second diode, a second resistor and a third resistor serially connected from the input terminal. A comparator is supplied with a voltage on a node between the first diode and the first resistor and a voltage on a node between the second resistor and the third resistor for comparative amplification. A transistor is connected between the output terminal and a second reference voltage and having a control terminal to receive an output from the first comparator.
    Type: Grant
    Filed: April 5, 2007
    Date of Patent: September 15, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryu Ogiwara, Daisaburo Takashima
  • Patent number: 7583114
    Abstract: A supply voltage sensing circuit comprises an internal power supply circuit, which provides a constant output voltage regardless of the supply voltage. A delay circuit generates a delayed signal by delaying a variation in the output voltage. A divider circuit generates a divided voltage by dividing the supply voltage at a certain division ratio. A p-type MOS transistor has a source given the delayed signal and a gate given the divided voltage and turns on when the supply voltage lowers below a certain value. An output circuit provides an output voltage based on a drain voltage on the p-type MOS transistor.
    Type: Grant
    Filed: March 9, 2007
    Date of Patent: September 1, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryu Ogiwara, Daisaburo Takashima
  • Patent number: 7561459
    Abstract: This disclosure concerns a semiconductor memory device including a ferroelectric capacitor; a cell transistor having a source connected to a first electrode of the ferroelectric capacitor; bit lines; word lines; n plate lines corresponding to n column blocks and connected to a second electrodes of the ferroelectric capacitors in the corresponding column blocks, respectively, the n column blocks being obtained by dividing the cell array into the n column blocks for every set of m columns, where n?2 and m?2; a plurality of reset transistors connected between the bit lines and the n plate lines; and m reset lines corresponding to the m columns within the column blocks and connected to gates of n reset transistors of the reset transistors, the n reset transistors being respectively provided in n columns respectively included in the n column blocks.
    Type: Grant
    Filed: September 13, 2007
    Date of Patent: July 14, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hidehiro Shiga, Daisaburo Takashima
  • Patent number: 7542325
    Abstract: A ferroelectric memory comprises a memory cell block of plural serially connected memory cells each including a cell transistor and a ferroelectric capacitor connected in parallel therewith. And the ferroelectric memory comprises a cell transistor resistance measuring circuit, a word line voltage controller, and a word line voltage generator. The cell transistor resistance measuring circuit measures a resistance of the cell transistor. The word line voltage controller controls a word line voltage applied to a gate of the cell transistor based on the resistance of the cell transistor. The word line voltage generator generates the word line voltage.
    Type: Grant
    Filed: October 17, 2007
    Date of Patent: June 2, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadashi Miyakawa, Daisaburo Takashima
  • Patent number: 7532499
    Abstract: A semiconductor integrated circuit device includes a semiconductor substrate and a plurality of cell transistors provided on a surface of the semiconductor substrate. A local bit line is provided above the cell transistors and electrically connected to one of a source diffusion layer and a drain diffusion layer of each of the cell transistors. Ferroelectric capacitors corresponding in number to the cell transistors, are provided above the local bit line, where each of the ferroelectric capacitors has an upper electrode and a lower electrode electrically connected to the other one of the source diffusion layer and drain diffusion layer of the corresponding one of the cell transistors. A plate line is provided above the upper electrodes and electrically connected to the upper electrodes. A reset transistor and a block selection transistor are provided on the surface of the semiconductor substrate.
    Type: Grant
    Filed: April 28, 2008
    Date of Patent: May 12, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Daisaburo Takashima