Reference Signal (e.g., Dummy Cell) Patents (Class 365/185.2)
  • Patent number: 9105330
    Abstract: Memory devices and methods are disclosed. One such method compares input data to stored data in a memory device and includes applying a first weight factor to a first string of memory cells coupled to a data line, where a first bit of the stored data is stored in the first string of memory cells; applying a second weight factor to a second string of memory cells coupled to the data line, where a second bit of the stored data is stored in the second string of memory cells; comparing a first bit of input data to the first bit of the stored data while the first weight factor is applied to the first string of memory cells; and comparing a second bit of the input data to the second bit of the stored data while the second weight factor is applied to the second string of memory cells.
    Type: Grant
    Filed: April 17, 2013
    Date of Patent: August 11, 2015
    Assignee: Micron Technology, Inc.
    Inventors: Kenneth J. Eldredge, Frankie F. Roohparvar, Luca de Santis, Tommaso Vali
  • Patent number: 9093124
    Abstract: A semiconductor memory device is disclosed. The semiconductor memory device includes a current mirror configured to include a current mirror section for current of a first line to a second line and transistors coupled in parallel, a detector configured to control a voltage of the first line based on voltages of sensing nodes, a fail bit set section configured to control a voltage of the second line, and a comparator configured to compare the voltage of the first line with the voltage of the second line and generate a pass and fail check signal based on the comparing result.
    Type: Grant
    Filed: December 18, 2012
    Date of Patent: July 28, 2015
    Assignee: SK Hynix Inc.
    Inventors: In Gon Yang, Sung Hoon Ahn
  • Patent number: 9087598
    Abstract: Embodiments provide a method for reading a target memory sector of a memory. The method comprises, based on read data corresponding to a plurality of memory sectors of the memory, estimating first one or more reference voltages and, using the first one or more reference voltages, performing a first read operation on the target memory sector. The method further comprises determining an error correcting code (ECC) decoding failure of the first read operation and, in response to determining the ECC decoding failure of the first read operation and based on read data corresponding to the target memory sector, updating the estimate of the first one or more reference voltages to generate second one or more reference voltages. The method also comprises using the second one or more reference voltages, performing a second read operation on the target memory sector.
    Type: Grant
    Filed: February 28, 2014
    Date of Patent: July 21, 2015
    Assignee: Marvell World Trade Ltd.
    Inventor: Xueshi Yang
  • Patent number: 9063192
    Abstract: A method comprises providing first and second semiconductor devices. Each device comprises a transistor having a split gate electrode including first and second gate portions. Each device has a respective ratio between an area of its first gate portion and a sum of areas of its first and second gate portions. For each device, a stress voltage is applied to the first gate portion, but not to the second gate portion. For each device, the first and second gate portions are biased with a common voltage, and data are collected indicating a respective degradation for each device due to the stress voltage. The degradation has a component due to time dependent dielectric breakdown (TDDB) and a component due to bias temperature instability. From the collected data extrapolation determines the degradation component due to TDDB.
    Type: Grant
    Filed: March 16, 2011
    Date of Patent: June 23, 2015
    Assignee: Taiwan Semiconductor Manufacturing Co., Ltd.
    Inventors: Yen-Chieh Huang, Ching-Huang Wang, Tsung-Yi Yu
  • Patent number: 9053804
    Abstract: Methods and apparatus are provided for computing reliability values, such as log likelihood ratios (LLRs), with reduced complexity for flash memory devices. Data from a flash memory device that stores M bits per cell using 2^M possible states is processed by obtaining at least two soft read voltage values corresponding to two reference voltages V0 and V1, wherein the two reference voltages V0 and V1 are between two adjacent states of the 2^M possible states; and converting the at least two soft read voltage values to a log likelihood ratio for a region between the two reference voltages V0 and V1 using probability density functions only for the two adjacent states. The soft read voltage values comprise, for example, hard decision read values obtained by a plurality of read retries of a given cell at a plurality of reference voltages and/or soft values obtained from the flash memory device.
    Type: Grant
    Filed: February 26, 2013
    Date of Patent: June 9, 2015
    Assignee: Seagate Technology LLC
    Inventors: Yunxiang Wu, Zhengang Chen
  • Patent number: 9053820
    Abstract: Techniques are disclosed herein for performing an Internal Data Load (IDL) to sense non-volatile storage elements. Read pass voltages that are applied to the two neighbor word lines to a selected word line may be adjusted to result in a more accurate IDL. The read pass voltage for one neighbor may be increased by some delta voltage, whereas the read pass voltage for the other neighbor may be decreased by the same delta voltage. In one aspect, programming of an upper page of data into a word line that neighbors a target word line is halted to allow lower page data in the target memory cells to be read using an IDL and preserved in data latches while programming the upper page in the neighbor word completes. Preservation of the lower page data provides for a cleaner lower page when later programming the upper page into the target memory cells.
    Type: Grant
    Filed: August 11, 2014
    Date of Patent: June 9, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Wenzhou Chen, Dana Lee, Zhenming Zhou, Guirong Liang
  • Patent number: 9047928
    Abstract: Circuitry for generating voltage levels operative to perform data operations on non-volatile re-writeable memory arrays are disclosed. In some embodiments an integrated circuit includes a substrate and a base layer formed on the substrate to include active devices configured to operate within a first voltage range. Further, the integrated circuit can include a cross-point memory array formed above the base layer and including re-writable two-terminal memory cells that are configured to operate, for example, within a second voltage range that is greater than the first voltage range. Conductive array lines in the cross-point memory array are electrically coupled with the active devices in the base layer. The integrated circuit also can include X-line decoders and Y-line decoders that include devices that operate in the first voltage range. The active devices can include other active circuitry such as sense amps for reading data from the memory cells, for example.
    Type: Grant
    Filed: June 23, 2014
    Date of Patent: June 2, 2015
    Assignee: Unity Semiconductor Corporation
    Inventors: Christophe Chevallier, Chang Hua Siau
  • Publication number: 20150146487
    Abstract: Provided are a non-volatile memory device and a method for erasing the non-volatile memory device having vertical channel layers formed with different widths varying by height and a plurality of memory cells stacked along the vertical channel layers, the method including increasing potentials of the vertical channel layers, and when potentials of word lines connected to the memory cells are increased, erasing the memory cells while lowering the potentials of the word lines beginning from a word line positioned in an area in which a width of the vertical channel layer is wide to a word line positioned in an area in which the width of the vertical channel layer is narrow.
    Type: Application
    Filed: April 2, 2014
    Publication date: May 28, 2015
    Applicant: SK hynix Inc.
    Inventor: Sung Wook JUNG
  • Patent number: 9042169
    Abstract: Cells of a solid-state, non-volatile memory are assigned to one of a plurality of groups. Each group is defined by expected symbols stored in the cells in view of actual symbols read from the cells. Based on cell counts within the groups, it can be determined that a shift in a reference voltage will reduce a collective bit error rate of the cells. The shift can be applied to data access operations affecting the cells.
    Type: Grant
    Filed: May 27, 2014
    Date of Patent: May 26, 2015
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Arvind Sridharan, Ara Patapoutian
  • Patent number: 9036417
    Abstract: Techniques for efficiently programming non-volatile storage are disclosed. A second page of data may efficiently be programmed into memory cells that already store a first page. Data may be efficiently transferred from single bit cells to multi-bit cells. Memory cells are read using at least two different read levels. The results are compared to determine a count how many memory cells showed a different result between the two reads. If the count is less than a threshold, then data from the memory cells is stored into a set of data latches without attempting to correct for misreads. If the count is not less than the threshold, then data from the memory cells is stored into the set of data latches with attempting to correct for misreads. A programming operation may be performed based on the data stored in the set of data latches.
    Type: Grant
    Filed: February 7, 2013
    Date of Patent: May 19, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Wenzhou Chen, Zhenming Zhou, Jun Wan, Deepanshu Dutta, Yi-Chieh Chen, Dana Lee
  • Patent number: 9036413
    Abstract: Cross-points of flash memory cell voltage distributions are determined by reading data from a portion of the flash memory two or more times using two or more different candidate reference voltages and determining corresponding decision patterns. The frequency of occurrence of the decision patterns in the data read from the flash memory is used to conceptually construct a histogram. The histogram is used to estimate the cross-points. Employing decision patterns enables multiple cross-point voltages to be determined with a minimum of read operations.
    Type: Grant
    Filed: October 21, 2013
    Date of Patent: May 19, 2015
    Assignee: Seagate Technology LLC
    Inventors: Yunxiang Wu, Abdel-Hakim Alhussien, Zhengang Chen, Sundararajan Sankaranarayanan, Erich F. Haratsch
  • Patent number: 9036429
    Abstract: A nonvolatile memory device including a memory cell arranged at a region where a word line and a bit line cross each other; a control signal generator configured to be enabled while the nonvolatile memory device operates in a test mode, and generate control signals which are not provided from an external device, based on a reference signal provided from the external device; and a control logic configured to control an operation for the memory cell according to the generated control signals.
    Type: Grant
    Filed: December 13, 2012
    Date of Patent: May 19, 2015
    Assignee: SK Hynix Inc.
    Inventors: Beom Seok Hah, Jung Hwan Lee, Ji Hwan Kim, Myung Cho
  • Publication number: 20150131384
    Abstract: In a nonvolatile memory device (4) provided in a semiconductor device, when data is erased based on a band-to-band tunneling scheme, supply of a boosted voltage to a memory cell (MC) to be erased is ended when a condition that an output voltage (VUCP) of a charge pump circuit (52) has recovered to a predetermined reference voltage is satisfied and additionally a condition that a predetermined reference time has elapsed since start of supply of the boosted voltage (VUCP) to the memory cell (MC) to be erased is satisfied.
    Type: Application
    Filed: August 29, 2012
    Publication date: May 14, 2015
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventors: Tomoya Ogawa, Takashi Ito, Mitsuhiro Tomoeda
  • Patent number: 9030873
    Abstract: A method of operating a semiconductor device includes storing a supplying condition of a read voltage inputted from an external source into an internal register to perform a read operation of memory cells, performing the read operation repetitively with changing levels of the read voltage according to the supplying condition of the read voltage in the event that the number of error bits in a data read from the memory cells exceeds an allowable range, and storing an iteration number of the read operation in the internal register in case the number of the error bits falls within the allowable range.
    Type: Grant
    Filed: December 17, 2012
    Date of Patent: May 12, 2015
    Assignee: SK Hynix Inc.
    Inventors: Sang Kyu Lee, Min Ho Her, Myung Su Kim
  • Patent number: 9013923
    Abstract: A method of operating a semiconductor device includes programming one of a drain dummy cell and a source dummy cell which are included in a cell string; and coupling a bit line to the cell string in response to program states of the drain dummy cell and the source dummy cell and a voltage level applied to a drain dummy line coupled to a gate of the drain dummy cell and a source dummy line coupled to a gate of the source dummy cell.
    Type: Grant
    Filed: September 6, 2012
    Date of Patent: April 21, 2015
    Assignee: SK Hynix Inc.
    Inventor: Young Soo Park
  • Patent number: 9007845
    Abstract: In performing a read operation of a memory transistor, a control circuit supplies a first voltage to a selected word line connected to a selected memory transistor. A second voltage is supplied to a non-selected word line connected to a non-selected memory transistor other than the selected memory transistor, the second voltage being higher than the first voltage. A third voltage is supplied to a bit line. A fourth voltage lower than the third voltage is supplied to, among source lines, a selected source line connected to a memory string including the selected memory transistor in a selected memory block. A fifth voltage substantially the same as the third voltage is supplied to, among the source lines, a non-selected source line connected to a non-selected memory string in the selected memory block.
    Type: Grant
    Filed: June 19, 2014
    Date of Patent: April 14, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Maejima, Natsuki Sakaguchi
  • Patent number: 9007839
    Abstract: A method of reading a nonvolatile memory device comprises applying a read voltage to a memory cell array to read selected memory cells, counting a number of the selected memory cells that have a threshold voltage higher or lower than the read voltage, and comparing the counted number with a reference value to determine a number of bits stored in the selected memory cells.
    Type: Grant
    Filed: June 12, 2013
    Date of Patent: April 14, 2015
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ji-Sang Lee, Moosung Kim
  • Patent number: 9007842
    Abstract: A method for determining a retention time in a solid state device (SSD), comprising the steps of providing a plurality of write operations to a memory, determining a reference voltage for each of the write operations, determining a difference between (i) the reference voltage after each of the write operations and (ii) a target reference voltage and if the difference is above a predetermined value, generating a flag indicating an excessive retention has occurred.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: April 14, 2015
    Assignee: Seagate Technology LLC
    Inventors: Zhengang Chen, Jeremy Werner, Ying Quan Wu, Erich F. Haratsch
  • Patent number: 9001553
    Abstract: A method of operating a resistive switching device includes applying a program stress to a two terminal resistive memory unit. The program stress is applied at a program voltage configured to change a state of the memory unit from a first state to a second state. The method further includes applying a verification/stabilization stress to the two terminal resistive memory unit. The verification/stabilization stress is applied at a verification/stabilization voltage. An erase stress is applied to the two terminal resistive memory unit. The erase stress is applied at an erase voltage configured to change a state of the memory unit from the second state to the first state. The verification/stabilization voltage is between the program voltage and the erase voltage.
    Type: Grant
    Filed: November 6, 2012
    Date of Patent: April 7, 2015
    Assignee: Adesto Technologies Corporation
    Inventor: Deepak Kamalanathan
  • Patent number: 9001588
    Abstract: A sense amplifier circuit of a nonvolatile semiconductor memory device is provided. The sense amplifier circuit includes a reference voltage generator, a sensing voltage generator and a comparator. The sensing voltage generator outputs a sensing voltage to a sensing node depending on a current flowing through a data line. A load transistor supplying a current to the data line is directly connected to a clamping node. The load transistor is included in a current mirror circuit. In a read operation, a low voltage drive operation is performed and a sensing speed and power consumption are properly controlled.
    Type: Grant
    Filed: December 14, 2012
    Date of Patent: April 7, 2015
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Eui-Seung Kim, Ji-Sung Kim, SeEun O
  • Patent number: 8995200
    Abstract: A sense amplifier is configured to sense a current from a selected bit cell of a non-volatile memory array and compare the sensed current to a reference current to determine a logic state stored in the bit cell. A controller is configured to perform a program/erase operation on at least a portion of the memory array to change a logic state of at least one bit cell of the portion of the memory array; determine a number of program/erase pulses applied to the at least one bit cell during the program/erase operation to achieve the change in logic state; and when the number of program/erase pulses exceeds a pulse count threshold, adjust the reference current of the sense amplifier for a subsequent program/erase operation.
    Type: Grant
    Filed: September 23, 2013
    Date of Patent: March 31, 2015
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Fuchen Mu, Chen He, Yanzhuo Wang
  • Patent number: 8995213
    Abstract: A nonvolatile memory device includes a memory cell array including a main cell area and a retention flag cell area, a retention check unit configured to compare a read result for retention flag cells included in the retention flag cell area to a reference value, and determine a retention state of the retention flag cells according to a comparison result, and a control logic configured to provide a retention check result based on the retention state to the external device in response to a retention check request provided from an external device.
    Type: Grant
    Filed: December 12, 2012
    Date of Patent: March 31, 2015
    Assignee: SK Hynix Inc.
    Inventor: In Hwan Song
  • Patent number: 8988942
    Abstract: Methods for operating a non-volatile storage system in which cross-coupling effects are utilized to extend the effective threshold voltage window of a memory cell and to embed additional information within the extended threshold voltage window are described. In some cases, additional information may be embedded within a memory cell storing the highest programming state if the memory cell is in a high boosting environment by splitting the highest programming state into two substates and programming the memory cell to one of the two substates based on the additional information. A memory cell may be in a high boosting environment if its neighboring memory cells are in a high programmed state. Additional information may also be embedded within a memory cell storing the lowest programming state if the memory cell is in a low boosting environment. The additional information may include error correction information.
    Type: Grant
    Filed: July 2, 2012
    Date of Patent: March 24, 2015
    Assignee: Sandisk Technologies Inc.
    Inventor: Eran Sharon
  • Publication number: 20150078082
    Abstract: A non-volatile memory device with a current injection sensing amplifier is disclosed.
    Type: Application
    Filed: March 15, 2013
    Publication date: March 19, 2015
    Inventors: Yao Zhou, Xiaozhou Qian, Ning Bai
  • Publication number: 20150078081
    Abstract: A trimmable current reference generator for use in a sense amplifier is disclosed
    Type: Application
    Filed: March 15, 2013
    Publication date: March 19, 2015
    Inventors: Yao Zhou, Xiaozhou Qian, Kai Man Yue, Guangming Lin
  • Publication number: 20150078078
    Abstract: A storage device includes non-volatile memory and a controller. A method performed in the data storage device includes receiving, at the controller, first data to be stored at the non-volatile memory. The method further includes sending, from the controller, the first data, first dummy data, and second dummy data to the non-volatile memory to be stored at respective logical pages of a single physical page in the non-volatile memory. The single physical page includes multiple storage elements that are programmable into multiple voltage states according to a mapping of bits to states. The first dummy data and the second dummy data prevent a storage element of the single physical page from being programmed to a particular voltage state of the multiple voltage states.
    Type: Application
    Filed: September 17, 2013
    Publication date: March 19, 2015
    Applicant: SANDISK TECHNOLOGIES INC.
    Inventors: MANUEL ANTONIO D'ABREU, DIMITRIS PANTELAKIS
  • Publication number: 20150078077
    Abstract: A nonvolatile semiconductor memory device includes a memory string that includes a plurality of first memory cells, a plurality of second memory cells, and a transistor electrically connected between the plurality of first memory cells and the plurality of second memory cells, and a control circuit that performs a program operation by applying a program voltage to a gate of a selected first memory cell among the plurality of first memory cells and a gate of a selected second memory cell among the plurality of second memory cells, a pass voltage lower than the program voltage to other memory cells in the plurality of first and second memory cells, and a control voltage to a gate of the transistor.
    Type: Application
    Filed: February 27, 2014
    Publication date: March 19, 2015
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Kazushige KANDA
  • Patent number: 8982635
    Abstract: A writing method of a semiconductor memory device includes applying a plurality of program voltages sequentially generated to a selected word line, and applying any one of a plurality of source selection line voltages to a source selection line when each of the plurality of program voltages is applied.
    Type: Grant
    Filed: June 21, 2013
    Date of Patent: March 17, 2015
    Assignee: SK Hynix Inc.
    Inventors: Tae Gyun Kim, Chi Wook An
  • Patent number: 8982634
    Abstract: The present invention provides a flash memory including a memory cell, a current limiter and a program voltage generator. The memory cell is programmed in response to a program current and a program voltage. The current limiter reflects amount of the program current by a data-line signal, e.g., a data-line voltage. The program voltage generator generates and controls the program voltage in response to the data-line voltage, such that the program current can track to a constant reference current.
    Type: Grant
    Filed: January 10, 2014
    Date of Patent: March 17, 2015
    Assignee: eMemory Technology Inc.
    Inventors: Yu-Hsiung Tsai, Yuan-Tai Lin, Ching-Yuan Lin, Chao-Wei Kuo, Shang-Wei Fang, Wein-Town Sun
  • Patent number: 8976583
    Abstract: Provided are a semiconductor memory device has improved read disturbance characteristics as well as improved retention characteristics at a high temperature, and a reading method thereof. The non-volatile semiconductor memory device includes at least one bit line; and a cell string configured to be coupled with the bit line respectively, and include normal memory cells and dummy memory cells that are alternately coupled with each other, where normal data are programmed and read to and from the normal memory cells, and dummy memory cells are programmed with dummy data.
    Type: Grant
    Filed: September 6, 2012
    Date of Patent: March 10, 2015
    Assignee: SK Hynix Inc.
    Inventor: Hyung-Seok Kim
  • Patent number: 8971122
    Abstract: Apparatus, methods, and other embodiments associated with group based read reference voltage management in flash memory are described. According to one embodiment, an apparatus includes a partition logic, a Vref memory, and a Vref logic. The partition logic is configured to assign respective cells in a flash memory device to respective groups of cells. The Vref memory is configured to store respective Vref values mapped to respective groups of cells. The read logic is configured to read a cell in the flash memory by determining a group to which the cell is assigned; determining a Vref mapped to the group; and using the Vref value to read the cell. In one embodiment, the apparatus includes an adaptation logic configured to selectively adapt respective Vref values mapped to the respective groups of cells.
    Type: Grant
    Filed: February 27, 2014
    Date of Patent: March 3, 2015
    Assignee: Marvell International Ltd.
    Inventors: Xueshi Yang, Gregory Burd
  • Patent number: 8971121
    Abstract: Embodiments of the present disclosure provide methods, devices, modules, and systems for operating memory cells. One method includes: performing an erase operation on a selected group of memory cells, the selected group including a number of reference cells and a number of data cells; performing a programming monitor operation on the number of reference cells as part of the erase operation; and determining a number of particular operating parameters associated with operating the number of data cells at least partially based on the programming monitor operation performed on the number of reference cells.
    Type: Grant
    Filed: August 20, 2013
    Date of Patent: March 3, 2015
    Assignee: Micron Technology, Inc.
    Inventors: Akira Goda, Andrei Mihnea
  • Patent number: 8964477
    Abstract: A gate voltage generator which supplies first gate voltage at erase verify time to a first selected word line to which a first memory cell included in N memory cells is connected, which supplies the first gate voltage at the erase verify time to a second selected word line to which a first reference cell included in M reference cells is connected, which supplies second gate voltage at the erase verify time to a first non-selected word line connected to a memory cell array, and which supplies third gate voltage at the erase verify time to a second non-selected word line connected to a reference cell array is included. An electric current which flows through a reference cell connected to the second non-selected word line is stronger than an electric current which flows through a memory cell connected to the first non-selected word line.
    Type: Grant
    Filed: April 3, 2013
    Date of Patent: February 24, 2015
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Kengo Tanaka
  • Patent number: 8964480
    Abstract: A number (Nwl) of programmed word lines in a block of NAND strings is determined by measuring a reference combined current (Iref) in the block when all of the memory cells are in a conductive state. Subsequently, to determine if a word line is a programmed word line, an additional combined current (Iadd) in the block is measured with a demarcation voltage applied to the selected word line. The selected word line is determined to be programmed word lines if Idd is less than Iref by at least a margin. Nwl can be used to adjust an erase-verify test of an erase operation by making the erase-verify test relatively hard to pass when the number is relatively small and relatively easy to pass when the number is relatively large. Or, Nwl can be used to identify a next word line to program in the block.
    Type: Grant
    Filed: July 1, 2013
    Date of Patent: February 24, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Man L Mui, Yingda Dong, Chris Avila
  • Patent number: 8964449
    Abstract: A semiconductor memory device selects one of a plurality of memory cells as a dummy memory cell. The dummy memory cell is connected to a bit line that is complementary to a bit line connected to a selected memory cell. This technique advantageously compensates capacitance of the bit line. The semiconductor memory device comprises a selected memory cell connected to a first bit line and a first word line, a dummy memory cell connected to a second bit line complementary to the first bit line and a second word line, and a sense amplifier connected to the first and second bit lines and configured to read data stored in the selected memory cell by simultaneously enablement of the first and second word lines.
    Type: Grant
    Filed: January 23, 2012
    Date of Patent: February 24, 2015
    Assignee: Hynix Semiconductor Inc.
    Inventors: Tae Sik Yun, Kang Seol Lee
  • Publication number: 20150049544
    Abstract: A semiconductor memory device includes at least one cell string to include a plurality of dummy memory cells and a plurality of memory cells connected in series between the plurality of dummy memory cells; and the peripheral circuit to control the at least one cell string so that a first type of data represented by a first number of bits is stored in at least one of the dummy memory cells and a second type of data represented by a second number of bits, the second number smaller than the first number, is stored in at least two of the plurality of memory cells.
    Type: Application
    Filed: January 7, 2014
    Publication date: February 19, 2015
    Applicant: SK hynix Inc.
    Inventor: Hee Youl LEE
  • Patent number: 8953373
    Abstract: Upon a read error, a flash memory controller adjusts a candidate reference voltage on successive read retries until either a read error no longer occurs or an optimal reference voltage is attained. Optimal reference voltages correspond to cross-points of flash memory cell voltage distributions. Cross-points can be determined by using different candidate reference voltages to read data from the memory and determining corresponding decision patterns. The frequency of occurrence of the decision patterns in the data read from the memory is used to conceptually construct a histogram. The histogram is used to estimate when a candidate reference voltage has been adjusted to a cross-point.
    Type: Grant
    Filed: October 11, 2013
    Date of Patent: February 10, 2015
    Assignee: LSI Corporation
    Inventors: Yunxiang Wu, Erich F. Haratsch, Yu Cai, Abdel-Hakim Alhussien
  • Patent number: 8953384
    Abstract: A sense amplifier has a reference cell current branch in which a reference cell determines a reference cell current, a column load converts the reference cell current to a reference voltage, and a feedback circuit to maintain the reference cell drain voltage. The sense amplifier also has a main cell current branch in which a main cell operationally selected from an array of flash memory cells determines a main cell current, a column load converts the main cell current to a main voltage, and a feedback circuit to maintain the main cell drain voltage. A differential amplifier compares the reference voltage with the main voltage and furnishes a logical level at its output depending on the relative values. A boost circuit has a pull up section coupled across the column load and a pull down section coupled across the main cell for accelerating the logical zero sensing time.
    Type: Grant
    Filed: July 31, 2012
    Date of Patent: February 10, 2015
    Assignee: Winbond Electronics Corporation
    Inventors: Johnny Chan, Koying Huang
  • Patent number: 8953383
    Abstract: A semiconductor memory device is kept in a busy state by controlling a ready/busy pad when a detection signal is output since an external voltage is less than a reference voltage, prevents generation of an operating voltage by a pump circuit by preventing generation of a pump clock, and resets a microcontroller by preventing generation of micro clock. Accordingly, the semiconductor memory device may be prevented from malfunctioning through a series of operations when the external voltage is less than the reference voltage.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: February 10, 2015
    Assignee: SK Hynix Inc.
    Inventors: Byoung Sung Yoo, Jin Su Park, Sang Don Lee
  • Patent number: 8953376
    Abstract: According to example embodiments, a read method of a nonvolatile memory device includes Disclosed is a read method of a nonvolatile memory device which includes selecting one of a plurality of vertical strings in a nonvolatile memory device, judging a channel length between a common source line and a selected one of the plurality of vertical strings, selecting a sensing manner corresponding to the judged channel length, and performing a sensing operation according to the selected sensing manner. The plurality of vertical strings may extend in a direction perpendicular to a substrate of the nonvolatile memory device.
    Type: Grant
    Filed: February 21, 2012
    Date of Patent: February 10, 2015
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sang-Wan Nam, Chiweon Yoon, Jung-Soo Kim
  • Patent number: 8953375
    Abstract: A semiconductor memory device includes an information generation unit configured to convert positions of threshold voltages of memory cells in threshold voltage distributions based on determination voltages included in an overlapping portion between the threshold voltage distributions to generate a plurality of position information codes, and an error correction unit configured to sequentially receive the plurality of position information codes and perform an error correction operation for data of the memory cells.
    Type: Grant
    Filed: August 22, 2012
    Date of Patent: February 10, 2015
    Assignee: SK Hynix Inc.
    Inventors: Jun-Rye Rho, Seok-Hwan Choi
  • Patent number: 8942042
    Abstract: A method of adjusting a threshold voltage of a ground selection transistor in a nonvolatile memory device includes providing a first voltage to a gate of a first ground selection transistor in a read operation and providing a second voltage to a gate of a second ground selection transistor in the read operation. The nonvolatile memory device includes at least one string, the string having string selection transistors, memory cells and the first and second ground selection transistors connected in series and stacked on a substrate.
    Type: Grant
    Filed: February 21, 2013
    Date of Patent: January 27, 2015
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ae-Jeong Lee, Bongyong Lee, Dongchan Kim, Jaesung Sim
  • Patent number: 8937838
    Abstract: An expected value associated with stored values in solid state storage, as well as a set of three or more points are obtained where the three or more points include a voltage and a value associated with stored values. Two points having ratios closest to the expected value are selected from the set. A voltage is determined based at least in part on the selected two points and the expected value.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: January 20, 2015
    Assignee: SK hynix memory solutions inc.
    Inventors: Xiangyu Tang, Lingqi Zeng, Jason Bellorado, Frederick K. H. Lee, Arunkumar Subramanian
  • Patent number: 8934303
    Abstract: A semiconductor memory device is operated by, inter alia: precharging a bit line, providing a first voltage to a coupling circuit for coupling the bit lines and cell strings of a plurality of memory cells, providing a program voltage to a selected word line coupled to a memory cell on which a program operation will be performed among the plurality of memory cells, providing a pass voltage to unselected word lines, providing a second voltage lower than the first voltage to the coupling circuit, discharging the bit line by loading program data, and providing a third voltage lower than the second voltage to the coupling circuit.
    Type: Grant
    Filed: June 27, 2012
    Date of Patent: January 13, 2015
    Assignee: SK Hynix Inc.
    Inventor: Young Soo Park
  • Patent number: 8934307
    Abstract: A voltage generator of a nonvolatile memory device includes a pump circuit for generating a pump output voltage by performing a pumping operation and raise or maintain the output voltage in response to a double enable signal or a single enable signal, a first regulator for comparing a first division voltage with a first reference voltage and generating the double enable signal according to a result of the comparison, a second regulator for comparing a second division voltage with a second reference voltage and outputting the voltage of the first level as a first regulation voltage, and a third regulator for comparing the second division voltage with the second reference voltage and generating the single enable signal according to a result of the comparison.
    Type: Grant
    Filed: September 6, 2012
    Date of Patent: January 13, 2015
    Assignee: SK Hynix Inc.
    Inventor: Gyo Soo Chu
  • Patent number: 8935117
    Abstract: A testing circuit in an integrated circuit indirectly measures a voltage at a node of other circuitry in the integrated circuit. The testing circuit includes a transistor having a control electrode, a first conducting electrode coupled to a first pad, a second conducting electrode coupled to a terminal of a power supply, and one or more switches for selectively coupling the control electrode to one of the node and a second pad. A method includes determining a relationship between drain current and gate voltage of the transistor when the control electrode is coupled to the second pad. A voltage at the node is determined by relating the current through the first conducting electrode of the transistor when control electrode is coupled to the node.
    Type: Grant
    Filed: March 9, 2012
    Date of Patent: January 13, 2015
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Walter Luis Tercariol, Richard T. L. Saez, Fernando Zampronho Neto, Ivan Carlos Ribeiro Nascimento
  • Patent number: 8929141
    Abstract: Erasing memory cells in certain 3-D NAND charge-storage memory arrays is achieved by rapidly charging vertical conductors using Gate Induced Drain Leakage (GIDL) current generated in select transistors. When bit line voltage drops below its nominal value, select line voltage is controlled to maintain a constant voltage difference between bit line voltage and select line voltage thus maintaining a gate-drain voltage difference in select transistors that provides sufficient GIDL current for erase.
    Type: Grant
    Filed: October 2, 2013
    Date of Patent: January 6, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui, Pao-Ling Koh
  • Patent number: 8929147
    Abstract: Methods, apparatuses, and systems for comparing threshold voltages of a plurality of flash memory cells to a plurality of reference voltages. A number of flash memory cells having threshold voltages that fall within each bin of a plurality of bins is determined. The plurality of bins each represent a plurality of threshold voltage ranges. A threshold voltage distribution of the plurality of flash memory cells is calculated based at least in part on the number of flash memory cells that fall into each of the bins.
    Type: Grant
    Filed: December 23, 2013
    Date of Patent: January 6, 2015
    Assignee: Marvell International Ltd.
    Inventors: Xueshi Yang, Zining Wu, Gregory Burd
  • Patent number: 8929154
    Abstract: A semiconductor structure includes a first strap cell, a first read port, and a first VSS terminal. The first strap cell has a first strap cell VSS region. The first read port has a first read port VSS region, a first read port read bit line region, and a first read port poly region. The first VSS terminal is configured to electrically couple the first strap cell VSS region and the first read port VSS region.
    Type: Grant
    Filed: October 6, 2011
    Date of Patent: January 6, 2015
    Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.
    Inventors: Jacklyn Chang, Derek C. Tao, Yukit Tang, Kuoyuan (Peter) Hsu
  • Patent number: 8923065
    Abstract: Each I/O channel between a controller and one or more memory dice of a memory device has a driver on one end and a receiver at the other end. The receiver is optionally terminated with a pseudo open-drain (“POD”) termination instead of the conventional center-tapped (“CTT”) termination to save energy. During a read operation, data is driven from the memory die to a POD terminated receiver circuit in the controller. With POD termination, the degradation in performance due to the more non-linear driver in the memory die, fabricated for example in the NAND technology processing, is alleviated by an adaptive reference voltage level adjustment in the receiver circuit of the controller. Optionally, the receiver circuit of a memory die is also provided with an adaptive reference level adjustment.
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: December 30, 2014
    Assignee: SanDisk Technologies, Inc.
    Inventor: Venkatesh Prasad Ramachandra