Error Correction During Refresh Cycle Patents (Class 714/754)
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Patent number: 8225171Abstract: A semiconductor memory device may include a parity generating circuit, a memory cell array, an error calculating circuit and an error corrector. The parity generating circuit generates parities having different number of bits according to types of a partial array self-refresh mode, and selects one of the parities to output a first parity. The error calculating circuit calculates an error based on a first data corresponding to the input data and a second parity corresponding to the first parity and outputs a first error data. The error corrector corrects the first data based on the first data and the first error data.Type: GrantFiled: February 14, 2008Date of Patent: July 17, 2012Assignee: Samsung Electronics Co., Ltd.Inventor: Bok-Gue Park
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Patent number: 8214720Abstract: Whether the comparison value of temporarily stored data which is read out from a flash memory by a host system exceeds a threshold value related to a bit error or not is checked, and if the comparison value exceeds the threshold value, the temporarily stored data which is read out is rewritten into the flash memory. If the temporarily stored data has an error, the error is corrected by an error correction part and then the data is rewritten. The threshold value includes, e.g., the number of readouts, the number of bit errors and the number of accumulated occurrences of bit errors. The present invention is suitable for prevention of bit errors due to read disturb and can recover the bit data which changes with time, and therefore makes it possible to improve the reliability of the flash memory by preventing occurrence of bit errors.Type: GrantFiled: January 3, 2008Date of Patent: July 3, 2012Assignee: MegaChips CorporationInventors: Shinji Tanaka, Tetsuo Furuichi
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Publication number: 20120159280Abstract: There is provided a method for controlling a nonvolatile memory apparatus in a nonvolatile memory system including a host interface, a memory controller, and a memory area. The method includes: checking a number of ECC fail bits, determining whether or not to replace a corresponding block, and replacing the block, while a read command provided from the host interface is performed; and replacing a block, which was not replaced during the read operation, with a block to be used as a replacement target during a write operation.Type: ApplicationFiled: July 29, 2011Publication date: June 21, 2012Applicant: Hynix Semiconductor Inc.Inventors: Wun Mo YANG, Kyeong Rho KIM, Myung Suk LEE, Jeong Soon KWAK
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Patent number: 8161346Abstract: According to one embodiment, a data refresh apparatus which refreshes data stored in a storage device having storage areas, comprises an error detector configured to detect a number of errors of data stored in a storage area of the storage device, an error correction unit configured to execute an error correction for the data stored in the storage area and generate corrected data, a refresh unit configured to write the corrected data to one of the storage areas, and a refresh controller configured to control an operation cycle of the refresh unit according to a number of times of write operations with respect to the storage area.Type: GrantFiled: May 30, 2008Date of Patent: April 17, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Tatsuo Hirose, Hidehito Izawa
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Publication number: 20120036411Abstract: Methods, apparatuses and systems are disclosed for preserving, verifying, and correcting data in DRAM device during a power-saving mode. In the power-saving mode, memory cells in the DRAM device may be refreshed using a self-refresh operation. This self-refresh operation may allow bit errors to occur in the DRAM device. However, by employing error correction coding (ECC), embodiments of the present invention may detect and correct these potential errors that may occur in the power-saving mode. Furthermore, a partial ECC check cycle is employed to check and correct a sub-set of the memory cells during a periodic self-refresh process that occurs during the power-saving mode.Type: ApplicationFiled: October 14, 2011Publication date: February 9, 2012Applicant: MICRON TECHNOLOGY, INC.Inventors: Yutaka Ito, Takuya Nakanishi
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Patent number: 8108750Abstract: A data storage subsystem that includes three data storage units, three check storage units, and an array controller coupled to the three data and three check storage units can tolerate failure of any three data and check storage units failures can be occur before data stored on the data storage subsystem is lost. Information is stored on the data storage subsystem as a symmetric Maximum Distance Separation code, such as a Winograd code, a Reed Solomon code, an EVENODD code or a derivative of an EVENODD code. The array controller determines the contents of the check storage units so that any three erasures of the data storage units and the check storage units can be corrected by the array controller. The array controller updates a block of data contained in any one of the data storage units and the check storage units using only six IO operations.Type: GrantFiled: May 11, 2007Date of Patent: January 31, 2012Assignee: International Business Machines CorporationInventors: Steven Robert Hetzler, Daniel Felix Smith, Shmuel Winograd
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Patent number: 8103929Abstract: Disclosed is a method and an apparatus for efficient ACKnowledgment/NonACKnowledgement (ACK/NACK) transmission in order to transmit forward data for multiple layers and support Hybrid Automatic Retransmission reQuest (HARQ) for each layer in a mobile communication system. The method includes determining whether transmission of the ACK/NACK is for a first layer or for layers higher than the first layer; and when the transmission of the ACK/NACK is for layers higher than the first layer, transmitting the reverse ACK/NACK by allocating resources to the higher layers with a quantity different from that of the first layer.Type: GrantFiled: September 11, 2007Date of Patent: January 24, 2012Assignee: Samsung Electronics Co., Ltd.Inventors: Hwan-Joon Kwon, Jin-Kyu Han, Jae-Hyun Park, Seung-Kyun Oh, Dong-Hee Kim, Jae-Chon Yu, Yeon-Ju Lim, Zhouyue Pi
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Patent number: 8074153Abstract: An error correction device is provided. When an error of an incorrect data group stored in a memory is detected, a memory controller of the error correction device executes a burst read, burst write or burst read-modify-write (RMW) operations to the memory instead of the conventional single read-modify-write (RMW) operation, thereby reducing the occupied bandwidth of the memory.Type: GrantFiled: August 11, 2010Date of Patent: December 6, 2011Assignee: Mediatek Inc.Inventors: Ching-Wen Hsueh, Li-Lien Lin
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Patent number: 8074139Abstract: A request change unit outputs a command as a request under control of a judgment control unit. A response condition determination unit determines a condition that is to be matched by a correct response which is to be returned from the other device-in-communication in reply to the command if the other device-in-communication operates in conformity with a protocol. A check unit checks a response received from the other device-in-communication in reply to the command, against the condition. If the received response does not match the condition but is correctable to match the condition as a result of the check, a response correction unit corrects the received response to match the condition under control of the judgment control unit.Type: GrantFiled: June 26, 2007Date of Patent: December 6, 2011Assignees: Panasonic Corporation, The University of TokyoInventors: Tadanori Tezuka, Tsutomu Sekibe, Shunichi Kuromaru, Junji Michiyama, Hiroshi Nakamura, Masaaki Kondo, Takashi Nanya, Masashi Imai, Nassu Tomoyuki Bogdan
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Patent number: 8055970Abstract: According to one embodiment of the invention, a computer implemented method for computing a data integrity algorithm on a data stream comprises the acts of initializing a plurality of threads, partitioning the data stream into a plurality of data stream segments, calculating a number of data integrity values from the plurality of data stream segments, and verifying the integrity of the data stream using the data integrity values. The plurality of threads are executed at generally the same time. Each of the data integrity values are derived from an associated data stream segment.Type: GrantFiled: November 13, 2006Date of Patent: November 8, 2011Assignee: Raytheon CompanyInventors: Brian N. Smith, Scott R Oksanen, Jon D. Johnson
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Patent number: 8055957Abstract: An integrated circuit device contains a flash memory, a flash control unit for controlling the rewriting and reading on the flash memory, and a processor unit. The processor unit includes a normal mode and a fail-safe mode as the operating states. In normal mode, when a defect is detected during the verify operation after writing data onto the flash memory then any further use of the flash memory is stopped. In fail-safe-mode, when a defect is detected during the verify operation after writing data onto the flash memory, the error is corrected and flash memory usage continues. The operating state is normal mode, and when the verify operation detects a defect after normal mode erase operation, the operation shifts to fail-safe mode.Type: GrantFiled: May 9, 2008Date of Patent: November 8, 2011Assignee: Renesas Electronics CorporationInventor: Takao Kondo
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Patent number: 8046663Abstract: A semiconductor memory device includes: a first bank and a second bank; one or more first data input/output pads disposed at one side of the first bank and used in access to data of the first bank; one or more second data input/output pads disposed at one side of the second bank and used in access to data of the second bank; a first cyclic redundancy code (CRC) generation circuit for generating a first CRC using a plurality of data output from the first bank and outputting the generated first CRC through the first data input/output pads; and a second CRC generation circuit for generating a second CRC using a plurality of data output from the second bank and outputting the generated second CRC through the second data input/output pads.Type: GrantFiled: June 29, 2007Date of Patent: October 25, 2011Assignee: Hynix Semiconductor Inc.Inventor: Hyuck-Soo Yoon
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Patent number: 8032810Abstract: This memory device comprises a word-line control circuit applying a read voltage and a soft-value read voltage as a word line voltage to a word line to generate soft-values. The soft-value read voltage is between an upper limit and a lower limit of each of plural threshold voltage distributions. A likelihood calculation circuit calculates a likelihood value of data stored in a memory cell based on the soft-value. An error correction circuit executes data error correction for the data read from the memory cell based on the likelihood value. A refresh control circuit controls a timing of a refresh operation for the memory cell based on the soft-value or the likelihood value.Type: GrantFiled: August 15, 2007Date of Patent: October 4, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Tatsuyuki Ishikawa, Mitsuaki Honma, Hironori Uchikawa
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Patent number: 7979752Abstract: Systems and methods for data loss protection are presented. In one embodiment, a data loss protection switch includes a first port, a second port, an error threshold management component and a multiplexer. Components of the data loss protection switch cooperatively operate to efficiently protect data. The first port receives information from a first data stream. The second port receives data from a second data stream. The error threshold management component analyzes errors in the first data stream and the second data stream. The multiplexer is controlled by the error threshold management component and selects among the first and second data streams based on the analysis.Type: GrantFiled: July 26, 2006Date of Patent: July 12, 2011Assignee: Cypress Semiconductor CorporationInventors: Palani Subbiah, Paul Scott
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Patent number: 7930614Abstract: A test apparatus is provided for testing memory under test which stores a data string including an error correction code in the form of additional data. The test apparatus comprises: a logic comparator which compares each of the data sets included in a data string read out from the memory under test with a corresponding anticipated value created beforehand; a data error count unit which counts the number of data sets that do not match the respective anticipated values; and a defect detection unit which provides a function whereby, in a case that the count value counted by the error count unit exceeds a predetermined upper limit number which is equal to or greater than 1, determination is made that the memory under test is defective.Type: GrantFiled: March 5, 2007Date of Patent: April 19, 2011Assignee: Advantest CorporationInventor: Shinya Sato
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Publication number: 20110060961Abstract: A computer system includes a memory controller coupled to a memory module containing several DRAMs. The memory module also includes a non-volatile memory storing row addresses identifying rows containing DRAM memory cells that are likely to lose data during normal refresh of the memory cells. Upon power-up, the data from the non-volatile memory are transferred to a comparator in the memory controller. The comparator compares the row addresses to row addresses from a refresh shadow counter that identify the rows in the DRAMs being refreshed. When a row of memory cells is being refreshed that is located one-half of the rows away from a row that is likely to loose data, the memory controller causes the row that is likely to loose data to be refreshed. The memory controller also includes error checking circuitry for identifying the rows of memory cells that are likely to lose data during refresh.Type: ApplicationFiled: November 10, 2010Publication date: March 10, 2011Applicant: Micro Technology, Inc.Inventor: Dean A. Klein
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Patent number: 7894289Abstract: A DRAM memory device includes several banks of memory cells each of which are divided into first and second sets of memory cells. The memory cells in the first set can be refreshed at a relatively slow rate to reduce the power consumed by the DRAM device. Error checking and correcting circuitry in the DRAM device corrects any data retention errors in the first set of memory cells caused by the relatively slow refresh rate. The memory cells in the second set are refreshed at a normal rate, which is fast enough that data retention errors do not occur. A mode register in the DRAM device may be programmed to select the size of the second set of memory cells.Type: GrantFiled: October 11, 2006Date of Patent: February 22, 2011Assignee: Micron Technology, Inc.Inventor: J. Thomas Pawlowski
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Patent number: 7877668Abstract: When a host system outputs a read command to a memory controller, it measures a load count of a memory area on which a read access load is imposed. Then, when the host system judges that the load count of a memory area reaches a predetermined count, it causes the memory controller to perform an error detection on the memory area. Further, when the host system finds that an error occurs in the memory area, it causes the memory controller to perform an error correction on the memory area. This can avoid or reduce unintended rewriting due to repeated readouts.Type: GrantFiled: May 5, 2008Date of Patent: January 25, 2011Assignee: MegaChips CorporationInventor: Takahiko Sugahara
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Patent number: 7870460Abstract: According to one embodiment, the controller controls a data refresh operation. The data refresh operation comprises a refresh-data read operation of reading L blocks of data by a head from a track to be refreshed on a disk, a data backup-write operation of writing the read data by the head to a backup-track on the disk, and a refresh-write operation of writing the read data by the head to the track to be refreshed after the backup-write operation. The controller sets the number L of blocks to a value that satisfies conditions for completing the backup-write operation and the refresh-write operation within a time corresponding to N revolutions of the disk from completion of the refresh-data read operation.Type: GrantFiled: October 29, 2009Date of Patent: January 11, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Taro Iketaki, Akio Mizuno, Yasuhiko Ichikawa, Takao Aoki
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Patent number: 7849387Abstract: In one embodiment, a quantum detector is provided to detect a vulnerability measure for a processor based on a processor metrics each associated with operation of a processor structure during a quantum, along with a controller to control an error mitigation unit based on the vulnerability measure. Other embodiments are described and claimed.Type: GrantFiled: April 23, 2008Date of Patent: December 7, 2010Assignee: Intel CorporationInventors: Arijit Biswas, Niranjan Soundararajan, Shubhendu Mukherjee
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Patent number: 7836374Abstract: A computer system includes a memory controller coupled to a memory module containing several DRAMs. The memory module also includes a non-volatile memory storing row addresses identifying rows containing DRAM memory cells that are likely to lose data during normal refresh of the memory cells. Upon power-up, the data from the non-volatile memory are transferred to a comparator in the memory controller. The comparator compares the row addresses to row addresses from a refresh shadow counter that identify the rows in the DRAMs being refreshed. When a row of memory cells is being refreshed that is located one-half of the rows away from a row that is likely to loose data, the memory controller causes the row that is likely to loose data to be refreshed. The memory controller also includes error checking circuitry for identifying the rows of memory cells that are likely to lose data during refresh.Type: GrantFiled: September 22, 2008Date of Patent: November 16, 2010Assignee: Micron Technology, Inc.Inventor: Dean A. Klein
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Patent number: 7779189Abstract: A method for pipeline arbitration including receiving a first request for a shared chip interface from a first pipeline, determining whether a response bus of the shared chip interface is needed by the first request, and if it is determined that the response bus is not needed by the first request, concluding that the first request needs just an address bus of the shared chip interface, arbitrating the first request with a second request for the shared chip interface received from a second pipeline for access to the address bus, sending the first request to the address bus if the first request wins the arbitration over the second request, and rejecting the first request if the second request wins the arbitration over the first request. A corresponding system and computer program product.Type: GrantFiled: February 21, 2008Date of Patent: August 17, 2010Assignee: International Business Machines CorporationInventors: Deanna P. Dunn, Garrett M. Drapala, Michael F. Fee, Pak-kin Mak, Craig R. Walters
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Patent number: 7764081Abstract: A Programmable Logic Device (PLD) is provided with configuration memory cells displaying a superior soft error immunity by combating single event upsets (SEUs) as the configuration memory cells are regularly refreshed from non-volatile storage depending on the rate SEUs may occur. Circuitry on the PLD uses a programmable timer to set a refresh rate for the configuration memory cells. Because an SEU which erases the state of a small sized memory cell due to collisions with cosmic particles may take some time to cause a functional failure, periodic refreshing will prevent the functional failure. The configuration cells can be DRAM cells which occupy significantly less space than the SRAM cells. Refresh circuitry typically provided for DRAM cells is reduced by using the programming circuitry of the PLD. Data in the configuration cells of the PLD are reloaded from either external or internal soft-error immune non-volatile memory.Type: GrantFiled: August 5, 2005Date of Patent: July 27, 2010Assignee: Xilinx, Inc.Inventors: Tim Tuan, Prasanna Sundararajan
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Patent number: 7760822Abstract: An encoder for encoding data from a communication channel, comprises a first address generator to generate a first address in accordance with the user data. A linear block encoder encodes the user data in response to the first address from the first generator. A transmitter transmits an output of the linear block encoder to the communication channel.Type: GrantFiled: November 9, 2006Date of Patent: July 20, 2010Assignee: Marvell International Ltd.Inventors: Gregory Burd, Zining Wu
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Patent number: 7742356Abstract: A semiconductor memory device includes a first refresh cycle changing circuit that changes a refresh cycle according to an auto-refresh mode, without giving influence to a refresh cycle according to a self-refresh mode, and a second refresh cycle changing circuit that changes a refresh cycle according to the self-refresh mode, without giving influence to a refresh cycle according to the auto-refresh mode. In this way, according to the present invention, the refresh cycle according to the auto-refresh mode and the refresh cycle according to the self-refresh mode can be controlled independently. Therefore, refresh operation considering the characteristic of each mode can be executed.Type: GrantFiled: December 4, 2007Date of Patent: June 22, 2010Assignee: Elpida Memory, Inc.Inventors: Chiaki Dono, Yasuji Koshikawa
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Patent number: 7712007Abstract: When memory cells enter an operation mode which performs only data holding, a control circuit controls the memory cells and an ECC circuit as follows. A plurality of data are read out to generate and store a check bit for error detection and correction. Refreshing is performed in a period within the error occurrence allowable range of an error correcting operation performed by the ECC circuit by using the check bit. Before a normal operation mode is restored from the operation mode which performs only data holding, an error bit of the data is corrected by using the check bit. In an entry/exit period, read/write and an ECC operation are sequentially performed for all the memory cells by a page mode operation. Memory cells connected to a word line which is not accessed by the page mode operation are sequentially activated and refreshed.Type: GrantFiled: September 14, 2006Date of Patent: May 4, 2010Assignee: Kabushiki Kaisha ToshibaInventors: Takeshi Nagai, Shinji Miyano
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Patent number: 7647543Abstract: An integrated system mitigates the effects of a single event upset (SEU) on a reprogrammable field programmable gate array (RFPGA). The system includes (i) a RFPGA having an internal configuration memory, and (ii) a memory for storing a configuration associated with the RFPGA. Logic circuitry programmed into the RFPGA and coupled to the memory reloads a portion of the configuration from the memory into the RFPGA's internal configuration memory at predetermined times. Additional SEU mitigation can be provided by logic circuitry on the RFPGA that monitors and maintains synchronized operation of the RFPGA's digital clock managers.Type: GrantFiled: September 27, 2006Date of Patent: January 12, 2010Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space AdministrationInventors: Tak-kwong Ng, Jeffrey A. Herath
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Patent number: 7631228Abstract: A system, method, and memory controller are provided that alters a memory command stream to a hardware memory. Data is written to the hardware memory and, after the data is stored in the memory, error correction code is received from the memory. Bit errors are identified based upon the error correction code that was received. The memory command stream is then altered based upon the number of bit errors that were identified. In one embodiment, altering the memory command stream includes adjusting a memory refresh rate, while in another embodiment, altering the memory command stream includes adjusting a memory usage delay.Type: GrantFiled: September 12, 2006Date of Patent: December 8, 2009Assignee: International Business Machines CorporationInventors: Mark Andrew Brittain, Warren Edward Maule
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Patent number: 7624324Abstract: A file control system performing DMA (direct memory access) transfer is provided. The file control system includes file control devices, and each of the file control devices is provided between a host computer and an external storage device. A first file control device among the file control devices checks for errors in the data read from a memory, changes the error detection code added to the read data from a first error detection code to a second error detection code, changes at least a part of the data when an error is detected, and executes DMA-transfer of the data, which is changed or is not changed, to a second file control device of the transfer destination.Type: GrantFiled: September 29, 2005Date of Patent: November 24, 2009Assignee: Fujitsu LimitedInventors: Yuuji Hanaoka, Toshiyuki Yoshida, Yuichi Ogawa, Terumasa Haneda, Kazunori Masuyama
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Patent number: 7613256Abstract: A multimedia distribution system is disclosed. The distribution system includes a transmitter unit that distributes content from a content provider to one or more wireless subscriber units. The transmitter unit includes a decoder configured to determine whether a plurality of incoming packets include one or more erasures, a transmitter configured to transmit the packets to a receiving unit, and an error detection code generator configured to generate an error detection code for each of the packets transmitted to the receiver unit, the error detection code being modified for each of the erased packets so that the receiver unit will be able to identify the erased packets.Type: GrantFiled: April 4, 2006Date of Patent: November 3, 2009Assignee: QUALCOMM IncorporatedInventors: Durk L. van Veen, Jai N. Subrahmanyam, Jinxia Bai, Murali Ramaswamy Chari
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Patent number: 7600065Abstract: For arbitrating access to a shared memory device among a plurality of masters, a master generates a request for access signal that is sent to the arbitrator concurrently with an indispensable command such as an auto-refresh command that is generated in series. The arbitrator generates an acknowledge signal sent to the master for indicating approval or rejection for access. Existing pins of the master are used for transmission of such arbitration signals.Type: GrantFiled: July 3, 2006Date of Patent: October 6, 2009Assignee: Samsung Electronics Co., Ltd.Inventor: Young-Min Lee
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Patent number: 7590904Abstract: An embodiment generally relates to a method of self-detecting an error in a field programmable gate array (FPGA). The method includes writing a signature value into a signature memory in the FPGA and determining a conclusion of a configuration refresh operation in the FPGA. The method also includes reading an outcome value from the signature memory.Type: GrantFiled: September 14, 2006Date of Patent: September 15, 2009Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space AdministrationInventors: Tak-Kwong Ng, Jeffrey A. Herath
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Patent number: 7587463Abstract: A main controller sends a “rewrite mode” command to an engine controller. Receiving the command, the engine controller 12 sends a “roger” status. This switches the mode from a print mode to a rewrite mode. In the rewrite mode, the engine controller 12 serves as a master and the main controller 11 serves as a slave, a communication which is necessary for rewriting of firmware takes place between the two, and the firmware is rewritten.Type: GrantFiled: June 17, 2003Date of Patent: September 8, 2009Assignee: Seiko Epson CorporationInventor: Takatoshi Sugita
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Patent number: 7565593Abstract: A memory controller and method that provide a read-refresh (also called “distributed-refresh”) mode of operation, in which every row of memory is read within the refresh-rate requirements of the memory parts, with data from different columns within the rows being read on subsequent read-refresh cycles until all rows for each and every column address have been read, scrubbing errors if found, thus providing a scrubbing function that is integrated into the read-refresh operation, rather than being an independent operation. For scrubbing, an atomic read-correct-write operation is scheduled. A variable-priority, variable-timing refresh interval is described. An integrated card self-tester and/or card reciprocal-tester is described. A memory bit-swapping-within-address-range circuit, and a method and apparatus for bit swapping on the fly and testing are described.Type: GrantFiled: November 10, 2006Date of Patent: July 21, 2009Assignee: Cray Inc.Inventors: R. Paul Dixon, David R. Resnick, Van L. Snyder
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Patent number: 7549102Abstract: A wireless communication device performs error correction decoding after combining newly received data from a new transmission of data and retransmitted received data from a retransmission of the data. The wireless communication device comprises a storage unit operable to store newly received data, a reception quality evaluation unit operable to evaluate reception quality for the retransmitted received data or reception quality for combined data obtained by combining the retransmitted received data with the newly received data stored in the storage unit, and a control unit operable to perform control as to whether to decode the retransmitted received data or the combined data according to the results of the evaluation.Type: GrantFiled: June 21, 2005Date of Patent: June 16, 2009Assignee: Fujitsu LimitedInventors: Syuuichi Murata, Atsushi Tanaka, Junichi Niimi, Takahiro Matusaki, Akihide Otonari, Yuka Araikawa, Kazuhisa Obuchi
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Patent number: 7546514Abstract: Systems and methods for implementing chip correct and fault isolation in computer memory systems are disclosed. An exemplary method may include interleaving check bits with a data word to form at least one interleaved data word. The method may also include writing the at least one interleaved data word to memory in critical word order zero. The method may also include performing a check and correct operation on the at least one interleaved data word before returning the data word to a requesting device.Type: GrantFiled: April 11, 2005Date of Patent: June 9, 2009Assignee: Hewlett-Packard Development Company, L.P.Inventor: Michael Kennard Tayler
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Patent number: 7526709Abstract: An error detection and correction circuit is connected to at least one memory bank of a CAM device. During background processing (i.e., when the CAM is not performing reading, writing or searching functions) the error detection and correction circuit tests all of the CAM locations that it is connected to in sequence. If an error is detected, the error detection and correction circuit rewrites the CAM location with the correct data. Multiple error correction and detection circuits can be used in the CAM device to test multiple CAM locations simultaneously.Type: GrantFiled: June 23, 2006Date of Patent: April 28, 2009Assignee: Micron Technology, Inc.Inventors: Alon Regev, Zvi Regev
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Patent number: 7509555Abstract: A radio apparatus is disclosed for improving the throughput of data transfer using a HARQ-based automatic retransmission. The radio apparatus performs a HARQ-based automatic retransmission. In this event, a redundancy version control unit identifies a redundancy version in the retransmission based on a redundancy version in the preceding transmission in which the need for retransmission arose. A HARQ processing unit performs rate matching on each of the systematic bits and parity bits of data to be retransmitted in accordance with the redundancy version identified by the redundancy version control unit.Type: GrantFiled: September 19, 2005Date of Patent: March 24, 2009Assignee: NEC CorporationInventor: Ryuichiro Ishizaki
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Patent number: 7509558Abstract: A method and apparatus for error correction of an encoded data stream. A demodulated data stream is saved in an input buffer. A first correction process is performed on-the-fly in the input buffer. The data is transferred to an external SDRAM after correction. A data frame is copied from the external SDRAM to an embedded SRAM. A multipass correction is started in the embedded SRAM. The corrected data frame is copied back from the embedded SRAM to the external SDRAM.Type: GrantFiled: July 1, 2004Date of Patent: March 24, 2009Assignee: Thomson LicensingInventors: Stefan Müller, Marten Kabutz, Xavier Lebegue
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Patent number: 7493531Abstract: Disclosed is a memory device including an error rate measurement circuit and a control circuit. The error rate measurement circuit, carrying a BIST circuit, reads out and writes data for an area for monitor bits every refresh period to detect an error rate (error count) with the refresh period. The control circuit performs control for elongating and shortening the refresh period so that a desired error rate will be achieved. The BIST circuit issues an internal command and an internal address and drives the DRAM from inside. The BIST circuit writes and reads out desired data, compares the monitor bits to expected values (error decision) and counts the errors.Type: GrantFiled: June 15, 2005Date of Patent: February 17, 2009Assignee: Elpida Memory, Inc.Inventors: Yutaka Ito, Takeshi Hashimoto
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Patent number: 7480774Abstract: A method for performing a common cancel (CC) function on a dynamic random access memory (DRAM) semiconductor device to improve reliability and speed of a memory system. The CC function rakes advantage of the intrinsic delays associated wit memory read operations at high clock frequencies, and the increased write latency commensurate with increased read latencies where non-zero larencies for read and write operations are the norm by permitting address and command ECC structures to operate in parallel with the address and command re-drive circuitt The CC function is extendable to future DDR2 and DDR3 operating requirements in which latency of higher frequency modes will increase due to the shift from 2 bit pre-fetch to 4 and 8 bit pre-fetch architecture.Type: GrantFiled: April 1, 2003Date of Patent: January 20, 2009Assignee: International Business Machines CorporationInventors: Wayne F. Ellis, Mark W. Kellogg, Daniel J. Phipps
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Patent number: 7464315Abstract: Disclosed is a semiconductor memory device having a data retention operating mode. When an entry into the data retention operating mode is performed, parity information on data of the memory cells is calculated and the error correction on the memory cells is carried out at a time of an exit from the data retention operating mode, by an ECC (Error Correction Circuit). The semiconductor memory device includes means for outputting from an NC pin flag information indicating that the semiconductor memory device is the one including the data retention operating mode, that the exit processing from the data retention operating mode is under way, and that the error correction cannot be performed.Type: GrantFiled: June 17, 2005Date of Patent: December 9, 2008Assignee: Elpida Memory, Inc.Inventors: Yutaka Ito, Eiji Yamasaki, Hidetoshi Iwai
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Patent number: 7461326Abstract: The information processing method of the present invention detects redundant circuits as described below by means of an information processor that is provided with: a storage unit for storing circuit operation information that uses hardware description language and a library for performing a logic synthesis of the circuit operation information and converting to a net list; and a display unit. The information processor hierarchically arranges statement by statement the circuit operation information that is stored in the storage unit, and then refers to the library, performs a logic synthesis of the circuit operation information that has been hierarchically arranged and converts to a net list. The information processor then detects redundant fault sites, which are sites that are logically redundant from the net list, and displays information showing the redundant circuits that contain the redundant fault sites on the display unit.Type: GrantFiled: July 6, 2005Date of Patent: December 2, 2008Assignee: NEC CorporationInventor: Keisuke Kanamaru
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Patent number: 7461320Abstract: A computer system includes a processor coupled to a DRAM through a memory controller. The processor switches the DRAM to a low power refresh mode in which DRAM cells are refreshed at a sufficiently low rate that data retention errors may occur. Prior to switching the DRAM to the low power refresh mode, the processor identifies a region of an array of DRAM cells that contains essential data that needs to be protected from such data retention errors. The processor then reads data from the identified region, and either the DRAM or the memory controller generates error checking and correcting syndromes from the read data. The syndromes are stored in the DRAM, and the low power refresh mode is then entered. Upon exiting the low power refresh mode, the processor again reads the data from the identified region, and the read data is checked and corrected using the syndromes.Type: GrantFiled: May 11, 2006Date of Patent: December 2, 2008Assignee: Micron Technology, Inc.Inventor: Dean A. Klein
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Patent number: 7447973Abstract: A computer system includes a memory controller coupled to a memory module containing several DRAMs. The memory module also includes a non-volatile memory storing row addresses identifying rows containing DRAM memory cells that are likely to lose data during normal refresh of the memory cells. Upon power-up, the data from the non-volatile memory are transferred to a comparator in the memory controller. The comparator compares the row addresses to row addresses from a refresh shadow counter that identify the rows in the DRAMs being refreshed. When a row of memory cells is being refreshed that is located one-half of the rows away from a row that is likely to loose data, the memory controller causes the row that is likely to loose data to be refreshed. The memory controller also includes error checking circuitry for identifying the rows of memory cells that are likely to lose data during refresh.Type: GrantFiled: November 7, 2005Date of Patent: November 4, 2008Assignee: Micron Technology, Inc.Inventor: Dean A. Klein
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Patent number: 7447974Abstract: A computer system includes a memory controller coupled to a memory module containing several DRAMs. The memory module also includes a non-volatile memory storing row addresses identifying rows containing DRAM memory cells that are likely to lose data during normal refresh of the memory cells. Upon power-up, the data from the non-volatile memory are transferred to a comparator in the memory controller. The comparator compares the row addresses to row addresses from a refresh shadow counter that identify the rows in the DRAMs being refreshed. When a row of memory cells is being refreshed that is located one-half of the rows away from a row that is likely to loose data, the memory controller causes the row that is likely to loose data to be refreshed. The memory controller also includes error checking circuitry for identifying the rows of memory cells that are likely to lose data during refresh.Type: GrantFiled: November 7, 2005Date of Patent: November 4, 2008Assignee: Micron Technology, Inc.Inventor: Dean A. Klein
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Patent number: 7447950Abstract: In a memory system, an ECC circuit is not inserted on a data path for data writing/reading. The ECC process is performed during the cycle of normal data reading/writing process, in such timing that it does not conflict with the data reading/writing process in order not to cause a substantial delay in the data writing/reading process. Specifically, the ECC process is performed during the cycle of burst transfer in which a plurality of data are successively input to or output from a shift register. Since no access is made to the memory cell array during the burst transfer cycle, the ECC process does not cause a delay in the reading/writing process.Type: GrantFiled: May 13, 2004Date of Patent: November 4, 2008Assignee: NEC Electronics CorporationInventors: Hiroyuki Takahashi, Hiroshi Furuta
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Publication number: 20080235555Abstract: Methods, systems, and apparatuses are provided for operating a cache comprising dynamic storage having an array of cells. At a refresh interval, the array of cells of the cache is refreshed. A determination is made whether an error is found in the cache at the refresh interval. If no error is found in the cache, the refresh interval is repeatedly increased by a predetermined amount until an error is found. If an error is found, the error is recovered from. A determination is made if a number of line deletions for the cache is a maximum number of line deletions for the cache. If the maximum number of line deletions is not attained, a line having the error is deleted, and the number of line deletions for the cache is increased. If the maximum number of line deletions for the cache is attained, the refresh interval is decreased by the predetermined amount.Type: ApplicationFiled: March 20, 2007Publication date: September 25, 2008Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Philip G. Emma, William Roehr
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Patent number: 7428685Abstract: The invention features a method including: (i) providing an interference signal S(t) from two beams directed along different paths, wherein the signal S(t) is indicative of changes in an optical path difference n{tilde over (L)}(t) between the different paths, where n is an average refractive index along the different paths, {tilde over (L)}(t) is a total physical path difference between the different paths, and t is time; (ii) providing one or more coefficients representative of one or more errors that cause the signal S(t) to deviate from an ideal expression of the form A1 cos(?Rt+?(t)+?1), where A1 and ?1 are constants, ?R is an angular frequency difference between the two beams before being directed along the different paths, and ?(t)=nk{tilde over (L)}(t), with k=2?/? and ? equal to a wavelength for the beams; (iii) calculating a linear combination of values of the signal S(t); and (iv) reducing the effect of the deviation of S(t) from the ideal expression on an estimate of {tilde over (L)}(t) using an eType: GrantFiled: February 17, 2005Date of Patent: September 23, 2008Assignee: Zygo CorporationInventors: Frank C. Demarest, Henry A. Hill
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Patent number: 7428687Abstract: A computer system includes a memory controller coupled to a memory module containing several DRAMs. The memory module also includes a non-volatile memory storing row addresses identifying rows containing DRAM memory cells that are likely to lose data during normal refresh of the memory cells. Upon power-up, the data from the non-volatile memory are transferred to a comparator in the memory controller. The comparator compares the row addresses to row addresses from a refresh shadow counter that identify the rows in the DRAMs being refreshed. When a row of memory cells is being refreshed that is located one-half of the rows away from a row that is likely to loose data, the memory controller causes the row that is likely to loose data to be refreshed. The memory controller also includes error checking circuitry for identifying the rows of memory cells that are likely to lose data during refresh.Type: GrantFiled: November 7, 2005Date of Patent: September 23, 2008Assignee: Micron Technology, Inc.Inventor: Dean A. Klein