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: 20240063819
    Abstract: Methods, systems, and apparatuses detect and mitigate a stall condition in an iterative decoder. A codeword is received and one or more of the plurality of bits in the codeword are flipped by a bit flipping decoder in each of a plurality of error correction iterations. In response to detecting a stall condition in the plurality of error correction iterations, a maximum stop condition is increased. The maximum stop condition is a maximum iteration count threshold or a maximum decoding time threshold. The maximum stop condition triggers a stopping of the bit flipping decoder if the codeword is not decoded when the maximum stop condition is satisfied.
    Type: Application
    Filed: August 18, 2022
    Publication date: February 22, 2024
    Inventors: Sivagnanam Parthasarathy, Mustafa N. Kaynak
  • Publication number: 20240063818
    Abstract: Methods, systems, and apparatuses detect and mitigate a stall condition in an iterative decoder. A codeword is received from a memory device. One or more of the plurality of bits in the codeword are flipped in each of a plurality of error correction iterations. Each bit is flipped using a first bit flipping criterion that includes comparing a first bit flipping threshold and an energy function of each bit. Responsive to the determining an iteration count threshold is satisfied and a parity violation count threshold is satisfied, one or more of the plurality of bits in the codeword are flipped using a second bit flipping criterion for one or more error correction iterations. The second bit flipping criterion differs from the first bit flipping criterion.
    Type: Application
    Filed: August 18, 2022
    Publication date: February 22, 2024
    Inventors: Mustafa N. Kaynak, Sivagnanam Parthasarathy
  • Publication number: 20240055061
    Abstract: Embodiments disclosed can include determining, for a wordline of the plurality of wordlines, a target read window budget (RWB) increase, wherein the target RWB increase corresponds to a maximum RWB increase associated with using a different PV voltage offset for each respective programming level of a memory cell. Embodiments can also include segmenting the plurality of wordlines into one or more wordline groups, wherein each wordline group comprises one or more wordlines. Embodiments can further include determining, for each wordline group, a target adjustment to a parameter of a memory access operation that is performed with respect to a memory cell associated with a wordline of the wordline group. Embodiments can include determining an aggregate RWB increase for the block in view of the target adjustment to the parameter of the memory access operation.
    Type: Application
    Filed: August 9, 2022
    Publication date: February 15, 2024
    Inventors: Mustafa N. Kaynak, Patrick R. Khayat, Sivagnanam Parthasarathy
  • Publication number: 20240055050
    Abstract: Embodiments disclosed can include determining, for a wordline of the plurality of wordlines, a respective value of a sensitivity metric that reflects a sensitivity of a threshold voltage of a memory cell associated with the wordline to a change in a threshold voltage of an adjacent memory cell. Embodiments can also include determining, for the wordline, that the respective value of the sensitivity metric satisfies a threshold criterion. Embodiments can further include responsive to determining that the respective value of the sensitivity metric satisfies the threshold criterion, associating the wordline with a first wordline group, wherein the first wordline group comprises one or more wordlines, and wherein each wordline of the one or more wordlines is associated with a respective value of the sensitivity metric that satisfies the threshold criterion. Embodiments can include performing, on a specified memory cell connected to the wordline associated with the first wordline group, a compensatory operation.
    Type: Application
    Filed: August 9, 2022
    Publication date: February 15, 2024
    Inventors: Mustafa N. Kaynak, Patrick R. Khayat, Sivagnanam Parthasarathy
  • Publication number: 20240054048
    Abstract: A system related to providing multi-layer code rates for special event protection with reduced performance penalty for memories is disclosed. Based on an impending stress event, extra error correction code data is utilized to encode user data obtained from a host. The user data and first error correction code data are written to a first block and the extra error correction code data is written to a second block. Upon stress event completion, pages having user data with the extra error correction code data are scanned. If pages of the first block are unable to satisfy reliability requirements, a touch-up process is executed on each page in the first block to reinstate the first block so that the extra error correction code data is no longer needed. The extra error correction code data is deleted from the second block and the second block is made available for user data.
    Type: Application
    Filed: August 9, 2022
    Publication date: February 15, 2024
    Inventors: Kishore Kumar Muchherla, Huai-Yuan Tseng, Mustafa N. Kaynak, Akira Goda, Sivagnanam Parthasarathy, Jonathan Scott Parry
  • Patent number: 11901911
    Abstract: Methods, systems, and apparatuses detect and mitigate a stall condition in an iterative decoder. A codeword is received from a memory device. One or more of the plurality of bits in the codeword are flipped in each of a plurality of error correction iterations. Each bit is flipped using a first bit flipping criterion that includes comparing a first bit flipping threshold and an energy function of each bit. Responsive to the determining an iteration count threshold is satisfied and a parity violation count threshold is satisfied, one or more of the plurality of bits in the codeword are flipped using a second bit flipping criterion for one or more error correction iterations. The second bit flipping criterion differs from the first bit flipping criterion.
    Type: Grant
    Filed: August 18, 2022
    Date of Patent: February 13, 2024
    Assignee: MICRON TECHNOLOGY, INC.
    Inventors: Mustafa N. Kaynak, Sivagnanam Parthasarathy
  • Publication number: 20240045759
    Abstract: A method may comprise detecting an error associated with accessing a set of data items. The set of data items are programmed to a respective memory page associated with a stripe of a plurality of stripes. In response to determining that the set of data items comprises one or more codewords, a first data recovery process is performed to recover the one or more codewords based at least in part on RAIN redundancy metadata. In response to determining that the set of data items comprises additional parity metadata, a second data recovery process is performed to recover the additional parity metadata based at least in part on LUN redundancy metadata. In response to determining that the set of data items comprises RAIN redundancy metadata, a first data reconstruction process is performed to regenerate the RAIN redundancy metadata based at least in part on one or more sets of codewords.
    Type: Application
    Filed: August 4, 2023
    Publication date: February 8, 2024
    Inventors: Zhengang Chen, Sivagnanam Parthasarathy
  • Patent number: 11886718
    Abstract: A memory device configured to descramble scrambled composite data. In one approach, the scrambled composite data is provided by an XOR (exclusive OR operation) of more than one data set scrambled with non-linear scramblers. A memory device is configured to receive scramble codes generated by non-linear scramblers and perform an XOR of the scrambled composite data with the scramble codes to remove scrambling from the composite data. In one example, the scrambled data sets are data to be written to a NAND device at more than one bit per cell density (e.g., MLC, TLC, QLC, PLC, etc.). For example, the scrambled data sets may be written to the NAND device in more than one programming pass. In one example, the scrambled composite data is used to read the scrambled data sets that have been written in a first programming pass.
    Type: Grant
    Filed: March 1, 2022
    Date of Patent: January 30, 2024
    Assignee: Micron Technology, Inc.
    Inventors: Patrick Robert Khayat, Sivagnanam Parthasarathy, Mustafa N. Kaynak
  • Patent number: 11875846
    Abstract: A memory device to determine a voltage window to read soft bit data. For example, in response to a read command, the memory device can read a group of memory cells at a plurality of test voltages to determine signal and noise characteristics, which can be used to determine an optimized read voltage for reading hard bit data and a voltage window between a first voltage and a second voltage for reading soft bit data. The soft bit data identifies exclusive or (XOR) of results read from the group of memory cells at the first voltage and at the second voltage respective. The memory device can provide a response to the read command based on the hard bit data and the soft bit data.
    Type: Grant
    Filed: November 24, 2021
    Date of Patent: January 16, 2024
    Assignee: Micron Technology, Inc.
    Inventors: James Fitzpatrick, Sivagnanam Parthasarathy, Patrick Robert Khayat, AbdelHakim S. Alhussien
  • Patent number: 11868202
    Abstract: A system includes a memory component to, upon completion of second pass programming in response to a multi-pass programming command, write a plurality of flag bits within a group of memory cells programmed by the multi-pass programming command. The system also includes a processing device, operatively coupled to the memory component. The processing device is to detect an error in attempting to read a top page of the group of memory cells, determine a number of first values within the plurality of flag bits, and in response to the number of first values not satisfying a threshold criterion, report, to a host computing device, an uncorrectable data error due to the top page of the group of memory cells being incompletely programmed.
    Type: Grant
    Filed: September 16, 2022
    Date of Patent: January 9, 2024
    Assignee: Micron Technology, Inc.
    Inventors: Qisong Lin, Vamsi Pavan Rayaprolu, Jiangang Wu, Sampath K. Ratnam, Sivagnanam Parthasarathy, Shao Chun Shi
  • Patent number: 11868639
    Abstract: At least one data of a set of data stored at a memory cell of a memory component is determined to be associated with an unsuccessful error correction operation. A determination is made as to whether a programming operation associated with the set of data stored at the memory cell has completed. The at least one data of the set of data stored at the memory cell that is associated with the unsuccessful error correction operation is recovered in response to determining that the programming operation has completed. Another memory cell of the memory component is identified in response to recovering the at least one data of the set of data stored at the memory cell that is associated with the unsuccessful error correction operation. The set of data including the recovered at least one data is provided to the other memory cell of the memory component.
    Type: Grant
    Filed: June 17, 2021
    Date of Patent: January 9, 2024
    Assignee: MICRON TECHNOLOGY, INC.
    Inventors: Sampath K. Ratnam, Vamsi Pavan Rayaprolu, Mustafa N. Kaynak, Sivagnanam Parthasarathy, Kishore Kumar Muchherla, Shane Nowell, Peter Feeley, Qisong Lin
  • Patent number: 11869605
    Abstract: Systems and methods are disclosed including a memory device and a processing device operatively coupled to the memory device. The processing device can perform operations including performing a read operation on a block of the memory device by applying a read reference voltage to a selected wordline of the block and applying a pass-through voltage having a first value to a plurality of unselected wordlines of the block; detecting a read error in response to performing the read operation; and setting the pass-through voltage to a second value, wherein the second value is greater than the first value.
    Type: Grant
    Filed: August 17, 2022
    Date of Patent: January 9, 2024
    Assignee: Micron Technology, Inc.
    Inventors: Kishore Kumar Muchherla, Mustafa N. Kaynak, Sampath K Ratnam, Peter Feeley, Sivagnanam Parthasarathy
  • Publication number: 20240004567
    Abstract: A processing device in a memory sub-system detects an occurrence of a triggering event, determines respective levels of charge loss associated with a first representative wordline of a block of a memory device and with a second representative wordline of the block of the memory device, and determines whether a difference between the respective levels of charge loss satisfies a threshold criterion. Responsive to determining that the difference between the respective levels of charge loss satisfies the threshold criterion, the processing device further determines that the block is in a uniform charge loss state.
    Type: Application
    Filed: September 19, 2023
    Publication date: January 4, 2024
    Inventors: Patrick R. Khayat, Steven Michael Kientz, Sivagnanam Parthasarathy, Mustafa N. Kaynak, Vamsi Pavan Rayaprolu
  • Patent number: 11861233
    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: Grant
    Filed: March 10, 2022
    Date of Patent: January 2, 2024
    Assignee: Micron Technology, Inc.
    Inventors: Jeffrey S. McNeil, Kishore Kumar Muchherla, Sivagnanam Parthasarathy, Patrick R. Khayat, Sundararajan Sankaranarayanan, Jeremy Binfet, Akira Goda
  • Patent number: 11854649
    Abstract: A processing device in a memory sub-system monitors a temperature associated with a block of a memory device, the block comprising a plurality of wordlines. The processing device further determines a first amount of time between when memory cells associated with a first wordline of the plurality of wordlines of the block were written and when memory cells associated with a last wordline of the plurality of wordlines of the block were written. That first amount of time is normalized according to the temperature associated with the block. The processing device further determines, based at last in part on the first amount of time and on an associated scaling factor, an estimate of when the block will reach a uniform charge loss state.
    Type: Grant
    Filed: February 18, 2022
    Date of Patent: December 26, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Patrick R. Khayat, Steven Michael Kientz, Sivagnanam Parthasarathy, Mustafa N. Kaynak, Vamsi Pavan Rayaprolu
  • Patent number: 11841753
    Abstract: An operating temperature of a memory sub-system is identified. It is determined whether the operating temperature satisfies a first temperature condition associated with a threshold temperature. Upon determining that the operating temperature satisfies the first temperature condition, one or more operations are performed on at least one data block at a memory component of the memory sub-system until the operating temperature changes to satisfy a second temperature condition associated with the threshold temperature. The one or more operations are selected to be performed based on a difference between the operating temperature and the threshold temperature.
    Type: Grant
    Filed: September 3, 2021
    Date of Patent: December 12, 2023
    Inventors: Shane Nowell, Sivagnanam Parthasarathy
  • Publication number: 20230393736
    Abstract: One of a plurality of compaction strategies to be performed on the memory device based on at least one characteristic of a memory device is identified. Each of the plurality of compaction strategies is to program host data from at least one single-level cell (SLC) of the memory device to at least one quad-level cell (QLC) of the memory device. One or more host data from a host system is received. A compaction operation on the one or more host data using the one of the plurality of compaction strategies is performed.
    Type: Application
    Filed: June 1, 2022
    Publication date: December 7, 2023
    Inventors: Vamsi Pavan Rayaprolu, Sampath K. Ratnam, Patrick R. Khayat, James Fitzpatrick, Kishore Kumar Muchherla, Sivagnanam Parthasarathy, Ashutosh Malshe
  • Publication number: 20230396269
    Abstract: A processing device in a memory sub-system reads a sense word from a memory device and executes a plurality of parity check equations on corresponding subsets of the sense word to determine a plurality of parity check equation results. The processing device further determines a syndrome for the sense word using the plurality of parity check equation results and determines whether the syndrome for the sense word satisfies a codeword criterion. Responsive to the syndrome for the sense word not satisfying the codeword criterion, the processing device performs an iterative low density parity check (LDPC) correction process using a scaled bit flip threshold to correct one or more errors in the sense word.
    Type: Application
    Filed: June 1, 2022
    Publication date: December 7, 2023
    Inventors: Eyal En Gad, Mustafa N. Kaynak, Sivagnanam Parthasarathy, Yoav Weinberg
  • Publication number: 20230393755
    Abstract: Embodiments disclosed can include determining, for each memory cell connected to each wordline, a respective value of a metric that reflects a sensitivity of a threshold voltage associated with the memory cell to a change in a threshold voltage of an adjacent cell and determining, for each wordline, based on the determined sensitivity for each memory cell, a respective aggregate measure of adjacent cell dependence. They can further include comparing the determined aggregate measure of adjacent cell dependence to a threshold dependence value. They can also include identifying a first wordline group having wordlines with high adjacent cell dependence and a second wordline group having wordlines with low adjacent cell dependence and storing a record referencing the wordlines of the second wordline group, the record indicating a corresponding location on the die of the memory device.
    Type: Application
    Filed: July 8, 2022
    Publication date: December 7, 2023
    Inventors: Mustafa N. Kaynak, Patrick R. Khayat, Sivagnanam Parthasarathy
  • Publication number: 20230393938
    Abstract: Systems and methods are disclosed including a memory device and a processing device operatively coupled to the memory device. The processing device can perform operations comprising selecting a source set of memory cells of the memory device, wherein the source set of memory cells are configured to store a first number of bits per memory cell; performing a data integrity check on the source set of memory cells to obtain a data integrity metric value; determining whether the data integrity metric value satisfies a threshold criterion; and responsive to determining that the data integrity metric value fails to satisfy the threshold criterion, causing the memory device to copy data from the source set of memory cells to a destination set of memory cells of the memory device, wherein the destination set of memory cells are configured to store a second number of bits per memory cell.
    Type: Application
    Filed: July 7, 2022
    Publication date: December 7, 2023
    Inventors: Vamsi Pavan Rayaprolu, Mustafa N. Kaynak, Sivagnanam Parthasarathy, Patrick Khayat, Sampath Ratnam, Kishore Kumar Muchherla, Jiangang Wu, James Fitzpatrick