Patents by Inventor Sivagnanam Parthasarathy

Sivagnanam Parthasarathy has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20230195358
    Abstract: A memory device having a bit-flipping decoder. The decoder having a plurality of circuits operatable to perform parallel computation to decode a codeword according to a plurality of columns of a parity matrix. The decoder is configured to provide columns of the parity matrix for processing in the plurality of circuits in an order where columns processed concurrently by the plurality of circuits in pipeline stages include no more than one parity column of the parity matrix.
    Type: Application
    Filed: December 20, 2021
    Publication date: June 22, 2023
    Inventors: Eyal En Gad, Mustafa N. Kaynak, Sivagnanam Parthasarathy, Yoav Weinberg
  • Publication number: 20230195385
    Abstract: A system can include a memory device and a processing device, operatively coupled with the memory device, to perform operations including receiving data to be stored on the memory device, storing a first copy of the data in a first set of memory cells of the memory device, and storing a second copy of the data in a second set of memory cells of the memory device. The operations can also include reading the first copy of the data and determining whether a threshold voltage of a cell in the first set of memory cells is within an overlapping range of voltage distributions, and reading the second copy of the data and determining whether the threshold voltage of a cell in the second set of memory cells is within an overlapping range of voltage distributions. They can also include using the second copy of the data.
    Type: Application
    Filed: March 10, 2022
    Publication date: June 22, 2023
    Inventors: Jeffrey S. McNeil, Kishore Kumar Muchherla, Sivagnanam Parthasarathy, Patrick Khayat, Sundararajan Sankaranarayanan, Jeremy Binfet, Akira Goda
  • Publication number: 20230195570
    Abstract: A memory device to use added known data as part of data written to memory cells with redundant data generated according to an error correction code (ECC). The code rate of the ECC may limit its capability to recover from excessive errors in the stored data. To reduce the errors, the added data retrieved from the memory cells can be corrected without using the ECC. Subsequently, remaining errors can be corrected via the ECC. Optionally, the added data can be configured to be the same as the data represented by an erased state of a subset of the memory cells such that when the subset is used to store the added data, the subset remains in the erased state to reduce wearing. Different subsets can be used to store added data for different write operations to distribute the benefit of reduced wearing.
    Type: Application
    Filed: December 9, 2022
    Publication date: June 22, 2023
    Inventors: Sivagnanam Parthasarathy, Kishore Kumar Muchherla, Akira Goda, Mustafa N. Kaynak
  • Patent number: 11676666
    Abstract: A memory device to perform a read disturb scan of unprogrammed memory cells. In one approach, a test read is performed on unprogrammed memory cells in a first memory block of a storage media (e.g., NAND flash) to provide a test result. Based on the test result, a portion of the unprogrammed cells for which a threshold voltage is above a predetermined voltage is determined. A determination is made whether the portion of the unprogrammed memory cells exceeds a predetermined limit. In response to determining that the portion exceeds the predetermined limit, data is moved from the first memory block to a second memory block of the storage media.
    Type: Grant
    Filed: September 4, 2020
    Date of Patent: June 13, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Sivagnanam Parthasarathy, Patrick Robert Khayat, Mustafa N. Kaynak
  • Patent number: 11675529
    Abstract: A processing device of a memory sub-system is configured to identify a plurality of blocks assigned to a first voltage bin of a plurality of voltage bins of a memory device; identify a subset of the plurality of blocks having a time after program (TAP) within a predetermined threshold period of time from a second TAP associated with a transition boundary between the first voltage bin and a subsequent voltage bin of the plurality of voltage bins; determine a threshold voltage offset associated with the subset of blocks; and associate the threshold voltage offset with the subsequent voltage bin.
    Type: Grant
    Filed: April 16, 2021
    Date of Patent: June 13, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Kishore Kumar Muchherla, Sampath K Ratnam, Shane Nowell, Peter Feeley, Sivagnanam Parthasarathy, Mustafa N Kaynak
  • Patent number: 11676664
    Abstract: A processing device of a memory sub-system is configured to detect a power on event that is associated with a memory device and indicates that power has been restored to the memory device; estimate a duration of a power off state preceding the power on event associated with the memory device; and update voltage bin assignments of a plurality of blocks associated with the memory device based on the duration of the power off state.
    Type: Grant
    Filed: August 8, 2022
    Date of Patent: June 13, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Kishore Kumar Muchherla, Sampath K. Ratnam, Shane Nowell, Sivagnanam Parthasarathy, Mustafa N. Kaynak, Karl D. Schuh, Peter Feeley, Jiangang Wu
  • Publication number: 20230176741
    Abstract: Described are systems and methods for validating read level voltage in memory devices. An example memory device comprises: a memory array comprising a plurality of memory cells electrically coupled to a plurality of wordlines; and a controller coupled to the memory array, the controller to perform operations comprising: causing a read level voltage to be applied to a specified wordline of the plurality of wordlines; receiving an actual bit count reflecting a number of memory cells that have their respective threshold voltages below the read level voltage; and responsive to determining that a difference of an expected bit count and the actual bit count exceeds a predetermined threshold value, adjusting the read level voltage.
    Type: Application
    Filed: November 2, 2022
    Publication date: June 8, 2023
    Inventors: Jeffrey S. McNeil, Eric N. Lee, Vamsi Pavan Rayaprolu, Sivagnanam Parthasarathy, Kishore Kumar Muchherla, Patrick R. Khayat, Violante Moschiano
  • Patent number: 11670396
    Abstract: A memory device to estimate a bit error count of data retrievable from a group of memory cells. For example, the memory device has a group of memory cells programmed to store a predetermined number of bits per memory cells to be read at a plurality of first voltages. The memory device determines a plurality of calibrated read voltages corresponding to the plurality of first voltages respectively, based on first signal and noise characteristics of the group of memory cells. The first signal and noise characteristics are used to compute second signal and noise characteristics of the group of memory cells for the calibrated read voltages. The second signal and noise characteristics are used in an empirical formula to compute an estimate of the bit error count of data retrievable from the group of memory cells using the calibrated read voltages.
    Type: Grant
    Filed: December 15, 2021
    Date of Patent: June 6, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Patrick Robert Khayat, Sivagnanam Parthasarathy, James Fitzpatrick
  • Patent number: 11663079
    Abstract: Exemplary methods, apparatuses, and systems include receiving a request for a segment of data. The requested segment data is one of a plurality of segments of data in a stripe of data. A failure to decode the requested segment is detected. Each of the plurality of segments in the stripe other than the requested segment are read. Reading each segment includes reading raw encoded data and attempting to decode the raw encoded data, the result of reading each segment including decoded data when decoding is successful and the raw encoded data when decoding fails. A combined result of each read is generated. The combining includes combining decoded data for segments that were successfully decoded and the raw encoded data for segments for which decoding failed. A statistical model for the requested segment is updated using the combined result. The requested segment is decoded using the updated statistical model.
    Type: Grant
    Filed: December 1, 2021
    Date of Patent: May 30, 2023
    Assignee: MICRON TECHNOLOGY, INC.
    Inventors: Dung V. Nguyen, Phong Sy Nguyen, Sivagnanam Parthasarathy
  • Patent number: 11662905
    Abstract: A memory sub-system configured to improve performance using signal and noise characteristics of memory cells measured during the execution of a command in a memory component. For example, the memory component is enclosed in an integrated circuit and has a calibration circuit. The signal and noise characteristics are measured by the calibration circuit as a byproduct of executing the command in the memory component. A processing device separate from the memory component transmits the command to the memory component, and receives and processes the signal and noise characteristics to identify an attribute about the memory component. Subsequently, an operation related to data stored in the memory component can be performed based on the attribute.
    Type: Grant
    Filed: December 15, 2021
    Date of Patent: May 30, 2023
    Assignee: Micron Technology, Inc.
    Inventors: James Fitzpatrick, Sivagnanam Parthasarathy, Patrick Robert Khayat, AbdelHakim S. Alhussien, Violante Moschiano
  • Patent number: 11657886
    Abstract: A memory device to generate intelligent, proactive responses to a read command. For example, signal and noise characteristics of a group of memory cells in a memory device are measured to determine a read voltage. An action is identified based on evaluation of the quality of data retrievable using the read voltage from the group of memory cells. While a response indicating the action is provided responsive to the command, the memory device can initiate the action proactively before a subsequent command, following the response, is received.
    Type: Grant
    Filed: June 11, 2021
    Date of Patent: May 23, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Sivagnanam Parthasarathy, James Fitzpatrick, Patrick Robert Khayat, AbdelHakim S. Alhussien
  • Publication number: 20230145358
    Abstract: A method includes receiving, by control logic of a memory device, a copyback clear command from a processing device; causing, in response to the copyback clear command, a page buffer to perform a dual-strobe read operation on first memory cells configured as single-level cells, the dual-strobe read operation including a soft strobe at a first threshold voltage and a hard strobe at a second threshold voltage that are sensed between threshold voltage distributions of the first memory cells; causing the page buffer to determine a number of one bit values within the threshold voltage distributions detected in a threshold voltage range between the first/second threshold voltages; and causing, in response to the number of one bit values not satisfying a threshold criterion, a copyback of data in the first memory cells to second memory cells configured as high-level cells without intervention from the processing device.
    Type: Application
    Filed: November 1, 2022
    Publication date: May 11, 2023
    Inventors: Jeffrey S. McNeil, Sivagnanam Parthasarathy, Kishore Kumar Muchherla, Patrick R. Khayat, Sead Zildzic, Violante Moschiano, James Fitzpatrick
  • Publication number: 20230122275
    Abstract: A method includes initiating a voltage calibration scan with respect to a block of a memory device, wherein the block is assigned to a first bin associated with a first set of read voltage offsets, and wherein the first bin is designated as a current bin, measuring a value of a data state metric for the block based on a second set of read voltage offsets associated with a second bin having an index value higher than the first bin, determining whether the value is less than a current value of the data state metric measured based on the first set of read voltage offsets, and in response to determining that the value is less than the current value, designating the second bin as the current bin.
    Type: Application
    Filed: December 19, 2022
    Publication date: April 20, 2023
    Inventors: Kishore Kumar Muchherla, Mustafa N. Kaynak, Sivagnanam Parthasarathy, Xiangang Luo, Peter Feeley, Devin M. Batutis, Jiangang Wu, Sampath K. Ratnam, Shane Nowell, Karl D. Schuh
  • Patent number: 11632132
    Abstract: A processing device in a memory system receives a request to read data from a memory device. In response to receiving the request, the processing device performs an iterative error correction process on the data, wherein at least one iteration after a first iteration in the error correction process uses a criterion that is based at least partially on a previous iteration or partial iteration, and wherein performing the iterative error correction process comprises flipping any bits in the data having an associated number of unsatisfied parity check equations that satisfies a threshold criterion associated with the previous iteration.
    Type: Grant
    Filed: September 16, 2021
    Date of Patent: April 18, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Eyal En Gad, Zhengang Chen, Sivagnanam Parthasarathy, Yoav Weinberg
  • Patent number: 11620074
    Abstract: A current memory access voltage distribution is measured for a memory page of a block family associated with a first voltage bin of a plurality of voltage bins at a memory device. The first voltage bin is associated with a first voltage offset. A current value for a reference voltage is determined based on the current memory access voltage distribution measured for the memory page. An amount of voltage shift for the memory page is determined based on the current value for the reference voltage a prior value for the reference voltage. The prior value for the reference voltage is associated with a prior memory access voltage distribution for the memory page. In response to a determination that the amount of voltage shift satisfies a voltage shift criterion, the block family is associated with a second voltage bin of the plurality of voltage bins. The second voltage bin is associated with a second voltage offset.
    Type: Grant
    Filed: March 16, 2021
    Date of Patent: April 4, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Kishore Kumar Muchherla, Devin M. Batutis, Xiangang Luo, Mustafa N. Kaynak, Peter Feeley, Sivagnanam Parthasarathy, Sampath Ratnam, Shane Nowell
  • Publication number: 20230086696
    Abstract: A plurality of codewords are programmed to one or more memory pages of a memory sub-system. Each memory page of the memory sub-system is associated with a logical unit of a plurality of logical units of the memory sub-system and at least one of a plane of a plurality of planes of the memory sub-system or a block of a plurality of blocks of the memory sub-system. Each codeword of the plurality of codewords comprises host data and base parity bits. A plurality of additional parity bits are programmed to the one or more memory pages of the memory sub-system, wherein each additional parity bit of the plurality of additional parity bits is associated with a codeword of the plurality of standard codewords. A first set of redundancy metadata is generated corresponding to each of the additional parity bits. The first set of redundancy metadata is programmed to a memory page separate from any memory page storing the additional parity bits.
    Type: Application
    Filed: September 17, 2021
    Publication date: March 23, 2023
    Inventors: Zhengang Chen, Sivagnanam Parthasarathy
  • Patent number: 11609857
    Abstract: Exemplary methods, apparatuses, and systems include receiving a read operation directed to an aggressor location. An integrity scan of a victim location of the aggressor location is performed to determine an error value for the victim location. Data from the aggressor location is copied to a cache in response to determining the error value for the victim location satisfies a first error value threshold. The cache is a different type of memory from the aggressor location.
    Type: Grant
    Filed: December 4, 2020
    Date of Patent: March 21, 2023
    Assignee: MICRON TECHNOLOGY, INC.
    Inventors: Saeed Sharifi Tehrani, Sivagnanam Parthasarathy, Aniryudh Reddy Durgam
  • Publication number: 20230074966
    Abstract: A memory device to manage the assignment of offset voltages for read operations, and to adjust read voltages using the offset voltages. The offset voltages are dynamically adjusted by a controller during operation of the memory device in response to read errors. In one approach, a first bin of offset voltages is assigned to a first region of a storage media. The first offset voltages are used to adjust read voltages for reading a page of first memory cells in the first region. The controller determines that at least one error has occurred in reading the page. In response to determining the error, the controller determines second offset voltages that can be used to read the first memory cell without causing a read error. Based on the second offset voltages, the controller identifies third offset voltages for assigning to the first region. The third offset voltages are used for adjusting read voltages for subsequent reads of pages in the first region.
    Type: Application
    Filed: November 11, 2022
    Publication date: March 9, 2023
    Inventors: Mustafa N. Kaynak, Sivagnanam Parthasarathy, Patrick Robert Khayat
  • Publication number: 20230062445
    Abstract: Processing logic in a memory device receives a command to execute a set of read operations having read voltage levels corresponding to a programming distribution associated with the memory device. A set of memory bit counts is determined, where each memory bit count corresponds to a respective bin of a set of bins associated with the multiple read voltage levels of the set of read operations. A valley center bin having a minimum memory bit count of the set of memory bit counts is determined. The processing logic determines that the minimum memory bit count of the valley center bin satisfies a condition and an adjusted read voltage level associated with the valley center bin is identified in response to the condition being satisfied.
    Type: Application
    Filed: February 28, 2022
    Publication date: March 2, 2023
    Inventors: Eric N. Lee, Violante Moschiano, Jeffrey S. McNeil, James Fitzpatrick, Sivagnanam Parthasarathy, Kishore Kumar Muchherla, Patrick R. Khayat
  • Publication number: 20230068702
    Abstract: Control logic in a memory device receives a request to read data from a memory array of a memory device, the request comprising an indication of a segment of the memory array where the data is stored, and determines whether a write temperature associated with the data is stored in a flag byte corresponding to the segment of the memory array. Responsive to determining that the write temperature associated with the data is stored in the flag byte, the control logic determines a cross-temperature for the data based on the write temperature and a read temperature at a time when the request to read the data is received, determines a program/erase cycle count associated with the segment of the memory array, and determines, based on the cross-temperature and the program/erase cycle count, whether to perform a corrective action to calibrate a read voltage level to be applied to the memory array to read the data from the segment.
    Type: Application
    Filed: February 2, 2022
    Publication date: March 2, 2023
    Inventors: Kishore Kumar Muchherla, Violante Moschiano, Akira Goda, Jeffrey S. McNeil, Jung Sheng Hoei, Sivagnanam Parthasarathy, James Fitzpatrick, Patrick R. Khayat