Patents by Inventor Hitoshi Shiga
Hitoshi Shiga 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: 8432737Abstract: When performing a word line leak test to determine a leak state of the word lines, the control circuit applies, from the voltage control circuit to the word lines connected to the memory cell array written with test pattern data, voltages corresponding to the test pattern data. Thereafter, it switches the transfer transistors to a nonconductive state, thereby setting the word lines in a floating state. After a lapse of a certain time from switching of the transfer transistors to a nonconductive state, it activates the sense amplifier circuit to perform a read operation in the memory cell array. Then it compares a result of the read operation with an expectation value corresponding to the test pattern data.Type: GrantFiled: August 25, 2011Date of Patent: April 30, 2013Assignee: Kabushiki Kaisha ToshibaInventor: Hitoshi Shiga
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Publication number: 20130070546Abstract: A nonvolatile semiconductor memory device according to the embodiment comprises a memory cell array including plural blocks arranged in a first direction, each block containing plural memory cells operative to store data; a row decoder including a faulty block information holder circuit operative to store faulty block information indicative that the block is a faulty block; and a faulty block detector circuit operative to, when each of block groups includes at least one of the plural blocks, subject one of the block groups to a first detection step of simultaneously and intensively referring to pieces of faulty block information respectively corresponding to the plural blocks in one of the block groups simultaneously to detect whether the block group contains a faulty block.Type: ApplicationFiled: March 19, 2012Publication date: March 21, 2013Applicant: Kabushiki Kaisha ToshibaInventors: Osamu Nagao, Hitoshi Shiga
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Patent number: 8331147Abstract: A nonvolatile semiconductor memory device comprises: a memory cell array configured by a plurality of first and second lines and a plurality of memory cells, each of the memory cells being selected by the first and second lines and being configured to store multiple-bit data in a nonvolatile manner; a data bus configured to transmit write data to be written to the plurality of memory cells, the write data being configured by a plurality of unit data; a column selection unit configured by a plurality of data latches, each of the data latches being configured to directly receive the unit data inputted from the data bus and to retain the unit data; and a control unit configured to control activation/non-activation of the data latches. During a programming operation, for each unit data inputted to the column selection unit, the control unit activates one of the data latches corresponding to a certain one of the memory cells where the unit data is to be stored.Type: GrantFiled: July 19, 2010Date of Patent: December 11, 2012Assignee: Kabushiki Kaisha ToshibaInventor: Hitoshi Shiga
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Patent number: 8331158Abstract: In writing operation, charge pumps of a memory apply any of first to n-th voltages which are different from each other. An application-voltage selector selects voltages to be applied to WLs among the first to n-th voltages. A word-line number register stores the number of WLs to which each of the first to n-th voltages is to be applied for the first to n-th voltages. A storage stores a correspondence table that stores a relationship between the number of WLs for each of the first to n-th voltages and the number of charge pumps allocated to the first to n-th voltages. A generation-voltage selector allocates charge pumps to generate the first to n-th voltages based on the correspondence table according to the number of WLs for each of the first to n-th voltages. Each charge pump generates any of the first to n-th voltages allocated by the generation-voltage selector.Type: GrantFiled: January 28, 2011Date of Patent: December 11, 2012Assignee: Kabushiki Kaisha ToshibaInventor: Hitoshi Shiga
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Patent number: 8327063Abstract: A memory system with a semiconductor memory device, in which a physical block of n-bits serves as an erase unit, wherein the address management of the memory device is performed by a logical block with m-bits, “m” being larger than “n” and expressed by a power of two, and wherein a n-bit portion continued from the head address in the logical block is defined as a first management unit corresponding to one physical block of the memory device, and a number of the remaining fraction portions each defined as a second management unit are gathered so as to correspond to one physical block of the memory device.Type: GrantFiled: March 17, 2009Date of Patent: December 4, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Hitoshi Shiga, Hidetaka Tsuji
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Patent number: 8205039Abstract: A nonvolatile semiconductor memory device according to one aspect of the present invention includes: a memory cell array provided to perform programming in page units; and a control circuit provided to control the programming. The control circuit includes: means that performs a first detection for memory cells in a part provided as a unit smaller than a page, concurrently with programming to memory cells to be written in a page; and means that subjects the memory cells in the page to a second detection that takes into consideration a failure relief due to a redundant region, when the number of memory cells of unwritten state in the part as detected by the first detection becomes equal to or less than a first constant, and that ends the program operation when the number of memory cells of unwritten state in the page becomes equal to or less than a second constant.Type: GrantFiled: March 17, 2010Date of Patent: June 19, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Osamu Nagao, Hitoshi Shiga
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Patent number: 8189395Abstract: A nonvolatile semiconductor memory that includes a memory cell array including a plurality of electrically writable memory cells; a plurality of word lines and a plurality of bit lines connected to the plurality of memory cells; and a data reading and programming control section. The data reading and programming control section includes: an adjacent memory cell data reading section; an adjacent memory cell data memory section; a reading voltage level control section; a data reading section for reading the data from a first memory cell at a plurality of reading voltages corresponding to a plurality of predetermined reading voltage verify levels controlled using the reading voltage level control section; and a data determining section for determining which data of 4-value data is programmed in the first memory cell based on the data which is read by the data reading section.Type: GrantFiled: November 1, 2010Date of Patent: May 29, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Hitoshi Shiga, Susumu Fujimura, Yoshihiko Shindo
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Publication number: 20120063234Abstract: According to one embodiment, a memory system includes a first nonvolatile semiconductor memory, a second nonvolatile semiconductor memory and a controller. The first memory has memory cells and executes a first operation that is at least one of write, read, and erase operations with respect to the memory cells. The first operation includes a first sub-operation and a second-sub operation that consume a current which is equal to or higher than a predetermined current. The second memory has memory cells and executes a second operation that is at least one of write, read, and erase operations with respect to the memory cells. The second operation includes a third sub-operation and a fourth sub-operation that consume a current which is equal to or higher than the predetermined current. The controller controls the first operation and the second operation of the first memory and the second memory.Type: ApplicationFiled: September 6, 2011Publication date: March 15, 2012Inventors: Hitoshi SHIGA, Masahiro Yoshihara
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Publication number: 20120051134Abstract: When performing a word line leak test to determine a leak state of the word lines, the control circuit applies, from the voltage control circuit to the word lines connected to the memory cell array written with test pattern data, voltages corresponding to the test pattern data. Thereafter, it switches the transfer transistors to a nonconductive state, thereby setting the word lines in a floating state. After a lapse of a certain time from switching of the transfer transistors to a nonconductive state, it activates the sense amplifier circuit to perform a read operation in the memory cell array. Then it compares a result of the read operation with an expectation value corresponding to the test pattern data.Type: ApplicationFiled: August 25, 2011Publication date: March 1, 2012Applicant: Kabushiki Kaisha ToshibaInventor: Hitoshi SHIGA
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Patent number: 8036034Abstract: A semiconductor storage device comprises: a sense amplifier circuit; a first data retaining circuit and a second data retaining circuit configured to retain data and threshold voltage information, the second data retaining circuit output the data and the threshold voltage information to the outside; and a control circuit configured to control operation. The sense amplifier circuit is configured to perform a data-read operation and a threshold-voltage-information read operation at the same time. The control circuit is configured to control read operations so that either one of the data or the threshold voltage information for which a read operation is finished earlier is output from the second data retaining circuit, and the other one of the data or the threshold voltage information for which a read operation is not finished yet is read from a memory cell array and retained in the first data retaining circuit.Type: GrantFiled: September 22, 2009Date of Patent: October 11, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Hitoshi Shiga, Yoshihisa Kondo
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Publication number: 20110228615Abstract: According to one embodiment, a semiconductor memory device includes unit structures. Each unit structure includes bit lines, memory cells, sense amplifiers, a first data line, a computing circuit, a second data line, and data latches. The bit lines are connected to memory cells. The sense amplifiers are connected to respective bit lines adjacent to each other. The first data line is commonly connected to the sense amplifiers. The computing circuit is connected to the first data line. The second data line is connected to the computing circuit. The data latches are connected to the second data line. The unit structures are independent from one another. At least one of the unit structures is a spare unit structure. One of the unit structures is configured to be replaceable with the spare unit structure.Type: ApplicationFiled: February 23, 2011Publication date: September 22, 2011Inventor: Hitoshi SHIGA
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Publication number: 20110205801Abstract: In writing operation, charge pumps of a memory apply any of first to n-th voltages which are different from each other. An application-voltage selector selects voltages to be applied to WLs among the first to n-th voltages. A word-line number register stores the number of WLs to which each of the first to n-th voltages is to be applied for the first to n-th voltages. A storage stores a correspondence table that stores a relationship between the number of WLs for each of the first to n-th voltages and the number of charge pumps allocated to the first to n-th voltages. A generation-voltage selector allocates charge pumps to generate the first to n-th voltages based on the correspondence table according to the number of WLs for each of the first to n-th voltages. Each charge pump generates any of the first to n-th voltages allocated by the generation-voltage selector.Type: ApplicationFiled: January 28, 2011Publication date: August 25, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Hitoshi SHIGA
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Patent number: 7978512Abstract: A semiconductor memory system includes: a memory cell array having a plurality of memory cells arranged therein, the plurality of memory cells capable of storing N bits of information in each memory cell (where N is a natural number more than 3, other than a power of two); a control circuit configured to control read, write, and erase operations on the memory cell array; and an ECC circuit configured to correct data read from the memory cell array, based on redundant data. The memory cells that share one of word lines and can be written or read at a time are configured to store multiple pages of data therein. A total amount of data stored in the multiple pages is set to a power-of-two number of bits, and the redundant data is stored in a residual portion of the multiple pages.Type: GrantFiled: September 11, 2009Date of Patent: July 12, 2011Assignee: Kabushiki Kaisha ToshibaInventor: Hitoshi Shiga
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Patent number: 7941588Abstract: A nonvolatile semiconductor device includes a first flash memory device; a second flash memory device in which data programming and/or reading is faster than in said first flash memory device; an address conversion table which correlates a logical address of a memory cell to a physical address designating said memory cell of said first and/or said second flash memory; an interface part which accepts an access request to a memory cell, an address conversion table search part which searches a physical address an access part which accesses a memory cell a counting part which counts the number of times a physical address has been accessed and generates an access count value of said physical address; a comparison part which compares whether said access count value of said physical address is more than a threshold or not; and a transmitting part which transmits data to said second flash memory device.Type: GrantFiled: September 28, 2007Date of Patent: May 10, 2011Assignee: Kabushiki Kaisha ToshibaInventor: Hitoshi Shiga
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Publication number: 20110044106Abstract: A nonvolatile semiconductor memory that includes a memory cell array including a plurality of electrically writable memory cells; a plurality of word lines and a plurality of bit lines connected to the plurality of memory cells; and a data reading and programming control section. The data reading and programming control section includes: an adjacent memory cell data reading section; an adjacent memory cell data memory section; a reading voltage level control section; a data reading section for reading the data from a first memory cell at a plurality of reading voltages corresponding to a plurality of predetermined reading voltage verify levels controlled using the reading voltage level control section; and a data determining section for determining which data of 4-value data is programmed in the first memory cell based on the data which is read by the data reading section.Type: ApplicationFiled: November 1, 2010Publication date: February 24, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hitoshi SHIGA, Susumu Fujimura, Yoshihiko Shindo
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Publication number: 20110044103Abstract: A nonvolatile semiconductor memory device comprises: a memory cell array configured by a plurality of first and second lines and a plurality of memory cells, each of the memory cells being selected by the first and second lines and being configured to store multiple-bit data in a nonvolatile manner; a data bus configured to transmit write data to be written to the plurality of memory cells, the write data being configured by a plurality of unit data; a column selection unit configured by a plurality of data latches, each of the data latches being configured to directly receive the unit data inputted from the data bus and to retain the unit data; and a control unit configured to control activation/non-activation of the data latches. During a programming operation, for each unit data inputted to the column selection unit, the control unit activates one of the data latches corresponding to a certain one of the memory cells where the unit data is to be stored.Type: ApplicationFiled: July 19, 2010Publication date: February 24, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Hitoshi SHIGA
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Patent number: 7859910Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array including a plurality of word lines; a parameter storage part which stores a parameter related to a programming voltage which is applied to a word line for programming data; a word line selection circuit which selects a word line among the plurality of word lines which is connected to a memory cell to be programmed with data; a voltage application circuit which applies a programming voltage to the selected word line according to the parameter; a verify circuit which performs verification of programmed data; a control part which outputs a signal for selecting a word line and repeats the operations of the voltage application circuit until the verification is successful; a calculation circuit which calculates an average value of the number of times the control part repeats the operations of the voltage application circuit per each word line; and a parameter setting circuit which sets the pType: GrantFiled: December 12, 2008Date of Patent: December 28, 2010Assignee: Kabushiki Kaisha ToshibaInventor: Hitoshi Shiga
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Patent number: 7843724Abstract: A nonvolatile semiconductor memory that includes a memory cell array including a plurality of electrically writable memory cells; a plurality of word lines and a plurality of bit lines connected to the plurality of memory cells; and a data reading and programming control section. The data reading and programming cortrol section includes: an adjacent memory cell data reading section; an adjacent memory cell data memory section; a reading voltage level control section; a data reading section for reading the data from a first memory cell at a plurality of reading voltages corresponding to a plurality of predetermined reading voltage verify levels controlled using the reading voltage level control section; and a data determining section for deterraining which data of 4-value data is programmed in the first memory cell based on the data which is read by the data reading section.Type: GrantFiled: September 28, 2007Date of Patent: November 30, 2010Assignee: Kabushiki Kaisha ToshibaInventors: Hitoshi Shiga, Susumu Fujimura, Yoshihiko Shindo
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Patent number: 7839678Abstract: A NAND type flash memory includes first to third memory cell transistors having current paths connected in series between one end of a current path of each of first and second selection transistors, and each having a control gate and a charge storage layer, the first and second memory cell transistors being adjacent to the first and second selection transistors, the third memory cell transistor being positioned between the first and second memory cell transistors, the third memory cell transistor holding data having not less than three bits, the first memory cell transistor holding 2-bit data in which middle and upper pages is written by skipping a lower page, and a lower page verify voltage being set when writing the middle page, and a middle page verify voltage is set when writing the upper page, changing a position of a threshold distribution of the first memory cell transistor.Type: GrantFiled: September 16, 2009Date of Patent: November 23, 2010Assignee: Kabushiki Kaisha ToshibaInventor: Hitoshi Shiga
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Patent number: 7826268Abstract: A nonvolatile semiconductor memory, has a first wire; a second wire adjacent to the first wire; a third wire disposed next to the second wire such that the second wire is disposed between the first wire and the third wire; a power supply circuit for setting each of the wires at a predetermined potential; and a determining circuit for determining presence or absence of a short circuit between the wires.Type: GrantFiled: September 23, 2008Date of Patent: November 2, 2010Assignee: Kabushiki Kaisha ToshibaInventors: Norihiro Fujita, Toshihiko Himeno, Hitoshi Shiga