Patents by Inventor Kazuhiro Kurihara

Kazuhiro Kurihara 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: 6865133
    Abstract: A memory circuit has a plurality of blocks which further comprises a plurality of regular sectors and a spare sector, wherein each sector further comprises a plurality of memory cells, and when a regular sector in a first block is defective, this defective regular sector is replaced with a spare sector in a second block. And responding to an address to be supplied, the regular sector corresponding to the supplied address in the first block and the spare selector in the second block are selected simultaneously during a first period, and after the first period, selection of one of the regular sector and the spare sector is maintained according to the result of redundancy judgment on whether the supply address matches with the redundant address.
    Type: Grant
    Filed: September 2, 2003
    Date of Patent: March 8, 2005
    Assignee: Fujitsu Limited
    Inventors: Yoshihiro Tsukidate, Kazuhiro Kurihara, Yasushi Kasa, Tsutomu Nakai, Andy Cheung
  • Publication number: 20040257873
    Abstract: A core-based multi-bit memory (400) having a dual-bit dynamic referencing architecture (408, 410) fabricated on the memory core (401). A first reference array (408) and a second reference array (410) are fabricated on the memory core (401) such that a reference cell pair (185) comprising one cell (182) of the first reference array (408) and a corresponding cell (184) of the second reference array (410) are read and averaged to provide a reference voltage for reading a data array(s).
    Type: Application
    Filed: June 20, 2003
    Publication date: December 23, 2004
    Inventors: Ming-Huei Shieh, Kazuhiro Kurihara
  • Patent number: 6819591
    Abstract: An exemplary memory sector erase method comprises the steps of pre-programming a first bit and a second bit of a plurality of core memory cells of a plurality of memory blocks of a target memory sector, pre-programming one of a third bit and a fourth bit of a first neighboring memory cell adjacent to the target memory sector, and erasing the first bit and the second bit of the plurality of core memory cells of the plurality of memory blocks. According to another embodiment, the method further comprises programming the one of the third bit and the fourth bit of the first neighboring memory cell after the erasing step.
    Type: Grant
    Filed: January 20, 2004
    Date of Patent: November 16, 2004
    Assignee: Spansion LLC
    Inventors: Kazuhiro Kurihara, Ming-Huei Shieh, Santosh Yachareni, Pau-Ling Chen
  • Patent number: 6813735
    Abstract: The present invention discloses methods and systems of accomplishing I/O-based redundancy for a memory device that includes two-bit memory cells. The memory device includes a core two-bit memory cell array and a redundant two-bit memory cell array. The configuration of the core two-bit memory cell array is non-uniform such that the two-bit memory cells therein are not arranged in a sequential order. Due to the non-uniform configuration, I/O based redundancy is accomplished by decoding the addresses with a redundant Y-decoder circuit and translating the addresses using an address translation circuit. The translated addresses identify the location of the two-bit memory cells within the non-uniform core two-bit memory cell array. The decoding of the addresses configures the redundant two-bit memory cell array to provide a configuration that matches the two-bit memory cells in the location identified by the translated address.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: November 2, 2004
    Assignee: FASL, LLC.
    Inventors: Kazuhiro Kurihara, Pau-Ling Chen
  • Patent number: 6813189
    Abstract: System for using a dynamic reference cell in a double-bit cell memory. A method is provided for reading and verifying a double bit core cell in a memory device. The memory device includes a dynamic reference cell and a fixed reference cell. The method comprises the steps of programming the dynamic reference cell using the fixed reference cell, and programming the double bit core cell using the dynamic reference cell. When the dynamic reference cell is located along with the core cell on the same word line, a constant current source added to a core cell data line operates during program verify to provide a current difference between the core cell and the dynamic reference cell.
    Type: Grant
    Filed: July 16, 2002
    Date of Patent: November 2, 2004
    Assignee: Fujitsu Limited
    Inventor: Kazuhiro Kurihara
  • Patent number: 6791880
    Abstract: A non-volatile memory read circuit having adjustable current sources to provide end of life simulation. A flash memory device comprising a reference current source used to provide a reference current for comparison to the current of a memory cell being read, includes an adjustable current source in parallel with the memory cell being read, and an adjustable current source in parallel with the reference current source. The current from the memory cell, reference current source, and their parallel adjustable current sources are input to cascode circuits for conversion to voltages that are compared by a sense amplifier. The behavior of the cascode circuits and sense amplifier in response to changes in the memory cell and reference current source may be evaluated by adjusting the adjustable current sources so that the combined current at each input to the sense amplifier simulates the current of the circuit after aging or cycling.
    Type: Grant
    Filed: May 6, 2003
    Date of Patent: September 14, 2004
    Assignee: FASL, LLC
    Inventors: Kazuhiro Kurihara, Binh Quang Le, Pau-Ling Chen, Darlene Hamilton, Edward Hsia
  • Publication number: 20040109371
    Abstract: A memory circuit has a plurality of blocks which further comprises a plurality of regular sectors and a spare sector, wherein each sector further comprises a plurality of memory cells, and when a regular sector in a first block is defective, this defective regular sector is replaced with a spare sector in a second block. And responding to an address to be supplied, the regular sector corresponding to the supplied address in the first block and the spare selector in the second block are selected simultaneously during a first period, and after the first period, selection of one of the regular sector and the spare sector is maintained according to the result of redundancy judgment on whether the supply address matches with the redundant address.
    Type: Application
    Filed: September 2, 2003
    Publication date: June 10, 2004
    Inventors: Yoshihiro Tsukidate, Kazuhiro Kurihara, Yasushi Kasa, Tsutomu Nakai, Andy Cheung
  • Patent number: 6744666
    Abstract: Embodiments of the present invention are directed to a method and system to minimize page programming time for page programmable memory devices. In one embodiment, the present invention comprises program logic that programs a page programmable memory device with a plurality of words during a page programming cycle and a detector coupled to the program logic that identifies a particular word in that plurality of words which does not require programming. When the detector identifies a particular word which does not require programming, it sends an indication to the program logic component which, in response to the signal, reduces the length of the page programming cycle.
    Type: Grant
    Filed: September 12, 2002
    Date of Patent: June 1, 2004
    Assignees: Advanced Micro Devices, Inc., Fujitsu Limited
    Inventors: Santosh Yachareni, Kazuhiro Kurihara, Ming-Huei Shieh, Pau-Ling Chen
  • Patent number: 6731703
    Abstract: Power level calculating circuit 10 and 11 calculate power levels at the input and output terminals, respectively, of a channel filter 6, and an adder 13 computes the difference between the two calculated power levels. An adder 13 corrects (i.e., subtracts) the difference obtained in the adder 12 from an AGC control signal output of an integrating circuit 9, and reports the correction output as antenna terminal reception power level to a base-band circuit 7. The correction output of the adder 13 is obtained by taking the extent of attenuation outside a desired wave band in the channel filter 6, and thus corresponds to accurate antenna terminal reception power level.
    Type: Grant
    Filed: December 8, 2000
    Date of Patent: May 4, 2004
    Assignee: NEC Corporation
    Inventor: Kazuhiro Kurihara
  • Patent number: 6721370
    Abstract: A phase correction circuit for a radio communication apparatus includes a variable gain amplifier and phase correction unit. The variable gain amplifier amplifies a transmission/reception signal on the basis of a gain variably set in accordance with a gain signal. The phase correction unit has a phase characteristic opposite to that of the variable gain amplifier, corrects the phase of the transmission/reception signal on the basis of the gain signal supplied to the variable gain amplifier, and cancels a phase change of the signal caused in the variable gain amplifier.
    Type: Grant
    Filed: October 20, 1999
    Date of Patent: April 13, 2004
    Assignee: NEC Corporation
    Inventor: Kazuhiro Kurihara
  • Patent number: 6713809
    Abstract: The present invention relates generally to semiconductor memory devices and more particularly to multi-bit flash electrically erasable programmable read only memory (EEPROM) devices that employ charge trapping within a floating gate to indicate a 0 or 1 bit state. A memory device is provided, according to an aspect of the invention, comprising a floating gate transistor having dual polysilicon floating gates with an isolation opening between floating gates.
    Type: Grant
    Filed: March 16, 2001
    Date of Patent: March 30, 2004
    Assignees: Advanced Micro Devices, Inc., Fujitsu Limited
    Inventors: Jusuke Ogura, Kazuhiro Kurihara, Masaru Yano, Hideki Komori, Tuan Pham, Angela Hui
  • Publication number: 20040052111
    Abstract: A system and method for column selection in a non-volatile memory cell array is disclosed. A group of memory cells is arranged in a rectangular array having rows (X-dimension) and columns (Y-dimension). Within a row, the sources and drains of the memory cells are connected to form a linear chain. A common word line is coupled to each gate in the row. A separate column line is coupled to each node between adjacent memory cells of the chain. A four column Y-decoder is used to select column lines for sense operations. A voltage source is applied to two of the four column lines during the sense operation. Current on one of the column lines may be sensed to provide a measurement for read or verification.
    Type: Application
    Filed: September 12, 2002
    Publication date: March 18, 2004
    Inventors: Tien-Chun Yang, Ming-Huei Shieh, Kazuhiro Kurihara, Pau-Ling Chen
  • Publication number: 20040012993
    Abstract: System for using a dynamic reference cell in a double-bit cell memory. A method is provided for reading and verifying a double bit core cell in a memory device. The memory device includes a dynamic reference cell and a fixed reference cell. The method comprises the steps of programming the dynamic reference cell using the fixed reference cell, and programming the double bit core cell using the dynamic reference cell. When the dynamic reference cell is located along with the core cell on the same word line, a constant current source added to a core cell data line operates during program verify to provide a current difference between the core cell and the dynamic reference cell.
    Type: Application
    Filed: July 16, 2002
    Publication date: January 22, 2004
    Inventor: Kazuhiro Kurihara
  • Publication number: 20040008151
    Abstract: A variable type antenna matching circuit includes an antenna, shape change detecting section, transmission/reception radio section, and variable type antenna matching section. The shape change detecting section detects a change in the shape of the housing of a portable terminal. The transmission/reception radio section transmits and receives signals. The variable type antenna matching section changes the input impedance between the antenna and the transmission/reception radio section in accordance with an output signal from the shape change detecting section.
    Type: Application
    Filed: June 4, 2003
    Publication date: January 15, 2004
    Inventor: Kazuhiro Kurihara
  • Patent number: 6643178
    Abstract: System for source side sensing in a memory device. The system includes a source side sensing circuit for use in a memory device to determine core cell data from core cell current. The source side sensing circuit includes a constant current source coupled to receive the core cell current, and a cascode circuit coupled to the constant current source to convert the core cell current to an output voltage that is representative of the core cell data.
    Type: Grant
    Filed: July 31, 2001
    Date of Patent: November 4, 2003
    Assignee: Fujitsu Limited
    Inventor: Kazuhiro Kurihara
  • Patent number: 6574139
    Abstract: A method for reading at least one programmed dual bit memory cell using a plurality of programmed dual bit reference cells. The reference cells are programmed with selected parameters to compensate for changes in the memory cell. The memory cell is read and compared to data in the reference cells to determine the memory cell data. Thus, changes to the memory cell over time are accounted for by programming the reference cells using the selected parameters.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: June 3, 2003
    Assignee: Fujitsu Limited
    Inventor: Kazuhiro Kurihara
  • Publication number: 20030081458
    Abstract: A method for reading at least one programmed dual bit memory cell using a plurality of programmed dual bit reference cells. The reference cells are programmed with selected parameters to compensate for changes in the memory cell. The memory cell is read and compared to data in the reference cells to determine the memory cell data. Thus, changes to the memory cell over time are accounted for by programming the reference cells using the selected parameters.
    Type: Application
    Filed: January 18, 2002
    Publication date: May 1, 2003
    Inventor: Kazuhiro Kurihara
  • Publication number: 20030039147
    Abstract: System for source side sensing in a memory device. The system includes a source side sensing circuit for use in a memory device to determine core cell data from core cell current. The source side sensing circuit includes a constant current source coupled to receive the core cell current, and a cascode circuit coupled to the constant current source to convert the core cell current to an output voltage that is representative of the core cell data.
    Type: Application
    Filed: July 31, 2001
    Publication date: February 27, 2003
    Inventor: Kazuhiro Kurihara
  • Patent number: 6525969
    Abstract: Methods and apparatus are disclosed for reading memory cells in a virtual ground memory core, wherein a memory cell is selected to be read and an adjacent memory cell is precharged so as to mitigate leakage current associated with the adjacent cell. Decoder circuitry and methods are disclosed for selecting the memory cell to be read and the adjacent cell to be precharged, which may be used in single bit and dual bit memory devices, and which provide drain-side or source-side current sensing in the read operation.
    Type: Grant
    Filed: August 10, 2001
    Date of Patent: February 25, 2003
    Assignees: Advanced Micro Devices, Inc., Fujitsu Limited
    Inventors: Kazuhiro Kurihara, Santosh K. Yachareni
  • Publication number: 20030021155
    Abstract: A method and system are disclosed for memory cell soft program and soft program verify, to adjust, or correct the threshold voltage between a target minimum and maximum, which may be employed in association with a dual bit memory cell architecture. The method includes applying one reference voltage signal to the over erased core cell, and a different reference voltage signal to the reference cell, comparing the two currents produced by each, selectively verifying proper soft programming of one or more bits of the cell, determining that the dual bit memory cell is properly soft programmed. The method may also comprise selectively re-verifying proper soft programming of the cells after selectively soft programming at least one or more bits of the cell.
    Type: Application
    Filed: April 9, 2001
    Publication date: January 30, 2003
    Inventors: Santosh K. Yachareni, Darlene G. Hamilton, Binh Q. Le, Kazuhiro Kurihara