Patents by Inventor Chandra C. Varanasi

Chandra C. Varanasi 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).

  • Patent number: 11243838
    Abstract: Embodiments of the present invention disclose methods and apparatuses for correcting errors in data stored in a solid state device. The solid state device may have a plurality of bits stored in multi-level memory cells. The method may include identifying one or more errors in a plurality of memory cells. The method may further include converting the erroneous cells to erasures. The method may further include correcting the one or more erasures.
    Type: Grant
    Filed: May 14, 2020
    Date of Patent: February 8, 2022
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20200272539
    Abstract: Embodiments of the present invention disclose methods and apparatuses for correcting errors in data stored in a solid state device. The solid state device may have a plurality of bits stored in multi-level memory cells. The method may include identifying one or more errors in a plurality of memory cells. The method may further include converting the erroneous cells to erasures. The method may further include correcting the one or more erasures.
    Type: Application
    Filed: May 14, 2020
    Publication date: August 27, 2020
    Applicant: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Patent number: 10706897
    Abstract: Apparatuses and methods for read threshold voltage selection are provided. One example method can include setting a first soft read threshold voltage and a second soft read threshold voltage based on a difference between a first number of memory cells that are read as being programmed to a first state when read using a first threshold voltage and a second number of memory that are read as being programmed to the first state when read using another threshold voltage.
    Type: Grant
    Filed: July 2, 2019
    Date of Patent: July 7, 2020
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Patent number: 10691538
    Abstract: Embodiments of the present invention disclose methods and apparatuses for correcting errors in data stored in a solid state device. The solid state device may have a plurality of bits stored in multi-level memory cells. The method may include identifying one or more errors in a plurality of memory cells. The method may further include converting the erroneous cells to erasures. The method may further include correcting the one or more erasures.
    Type: Grant
    Filed: September 25, 2018
    Date of Patent: June 23, 2020
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20190325921
    Abstract: Apparatuses and methods for read threshold voltage selection are provided. One example method can include setting a first soft read threshold voltage and a second soft read threshold voltage based on a difference between a first number of memory cells that are read as being programmed to a first state when read using a first threshold voltage and a second number of memory that are read as being programmed to the first state when read using another threshold voltage.
    Type: Application
    Filed: July 2, 2019
    Publication date: October 24, 2019
    Inventor: Chandra C. Varanasi
  • Patent number: 10354700
    Abstract: Apparatuses and methods for read threshold voltage selection are provided. One example method can include setting a first soft read threshold voltage and a second soft read threshold voltage based on a difference between a first number of memory cells that are read as being programmed to a first state when read using a first threshold voltage and a second number of memory that are read as being programmed to the first state when read using another threshold voltage.
    Type: Grant
    Filed: August 23, 2018
    Date of Patent: July 16, 2019
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20190026182
    Abstract: Embodiments of the present invention disclose methods and apparatuses for correcting errors in data stored in a solid state device. The solid state device may have a plurality of bits stored in multi-level memory cells. The method may include identifying one or more errors in a plurality of memory cells. The method may further include converting the erroneous cells to erasures. The method may further include correcting the one or more erasures.
    Type: Application
    Filed: September 25, 2018
    Publication date: January 24, 2019
    Applicant: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20180366164
    Abstract: Apparatuses and methods for read threshold voltage selection are provided. One example method can include setting a first soft read threshold voltage and a second soft read threshold voltage based on a difference between a first number of memory cells that are read as being programmed to a first state when read using a first threshold voltage and a second number of memory that are read as being programmed to the first state when read using another threshold voltage.
    Type: Application
    Filed: August 23, 2018
    Publication date: December 20, 2018
    Inventor: Chandra C. Varanasi
  • Patent number: 10120753
    Abstract: Embodiments of the present invention disclose methods and apparatuses for correcting errors in data stored in a solid state device. The solid state device may have a plurality of bits stored in multi-level memory cells. The method may include identifying one or more errors in a plurality of memory cells. The method may further include converting the erroneous cells to erasures. The method may further include correcting the one or more erasures.
    Type: Grant
    Filed: May 26, 2015
    Date of Patent: November 6, 2018
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Patent number: 10121521
    Abstract: Apparatuses and methods for read threshold voltage selection are provided. One example method can include setting a first soft read threshold voltage and a second soft read threshold voltage based on a difference between a first number of memory cells that are read as being programmed to a first state when read using a first threshold voltage and a second number of memory that are read as being programmed to the first state when read using another threshold voltage.
    Type: Grant
    Filed: December 11, 2017
    Date of Patent: November 6, 2018
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Patent number: 9985651
    Abstract: Apparatuses and methods for soft read threshold location calibration are provided. One example method can include selecting read threshold sets (RTSs), and determining log-likelihood-ratios (LLRs) based on a number of decisions that correspond to each bin associated with the selected RTSs. Low-density parity-check (LDPC) codewords are decoded using the determined LLRs, and a RTS of the RTSs yielding a least number of failed codewords decoded using the determined LLRs is identified.
    Type: Grant
    Filed: May 25, 2017
    Date of Patent: May 29, 2018
    Assignee: Micron Technology, Inc.
    Inventors: Chandra C. Varanasi, Gerald L. Cadloni
  • Publication number: 20180102146
    Abstract: Apparatuses and methods for read threshold voltage selection are provided. One example method can include setting a first soft read threshold voltage and a second soft read threshold voltage based on a difference between a first number of memory cells that are read as being programmed to a first state when read using a first threshold voltage and a second number of memory that are read as being programmed to the first state when read using another threshold voltage.
    Type: Application
    Filed: December 11, 2017
    Publication date: April 12, 2018
    Inventor: Chandra C. Varanasi
  • Patent number: 9911466
    Abstract: Apparatuses and methods for read threshold voltage selection are provided. One example method can include setting a first soft read threshold voltage and a second soft read threshold voltage based on a difference between a first number of memory cells that are read as being programmed to a first state when read using a first threshold voltage and a second number of memory that are read as being programmed to the first state when read using another threshold voltage.
    Type: Grant
    Filed: February 16, 2016
    Date of Patent: March 6, 2018
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20170264312
    Abstract: Apparatuses and methods for soft read threshold location calibration are provided. One example method can include selecting read threshold sets (RTSs), and determining log-likelihood-ratios (LLRs) based on a number of decisions that correspond to each bin associated with the selected RTSs. Low-density parity-check (LDPC) codewords are decoded using the determined LLRs, and a RTS of the RTSs yielding a least number of failed codewords decoded using the determined LLRs is identified.
    Type: Application
    Filed: May 25, 2017
    Publication date: September 14, 2017
    Inventors: Chandra C. Varanasi, Gerald L. Cadloni
  • Publication number: 20170236562
    Abstract: Apparatuses and methods for read threshold voltage selection are provided. One example method can include setting a first soft read threshold voltage and a second soft read threshold voltage based on a difference between a first number of memory cells that are read as being programmed to a first state when read using a first threshold voltage and a second number of memory that are read as being programmed to the first state when read using another threshold voltage.
    Type: Application
    Filed: February 16, 2016
    Publication date: August 17, 2017
    Inventor: Chandra C. Varanasi
  • Patent number: 9697892
    Abstract: The present disclosure includes apparatuses, methods, and non-transitory computer-readable storage mediums for generation and application of gray codes. One example method comprises: selecting a particular N-bit member as a root member for a plurality of N-bit gray codes each comprising X members such that each of the plurality of N-bit gray codes comprise a same root member; and generating X?1 remaining members of the respective plurality of N-bit gray codes by performing X?1 member generation iterations, wherein each ith iteration of the X?1 member generation iterations generates respective ith members of the plurality of N-bit gray codes based on ith?1 members, with each one of the respective ith members comprising only those eligible neighbor members of a respective one of the ith?1 members, and with ā€œiā€ being a whole number index from 1 to X?1.
    Type: Grant
    Filed: October 4, 2016
    Date of Patent: July 4, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Chandra C. Varanasi, Bruce A. Liikanen
  • Patent number: 9692449
    Abstract: Apparatuses and methods for soft read threshold location calibration are provided. One example method can include selecting read threshold sets (RTSs), and determining log-likelihood-ratios (LLRs) based on a number of decisions that correspond to each bin associated with the selected RTSs. Low-density parity-check (LDPC) codewords are decoded using the determined LLRs, and a RTS of the RTSs yielding a least number of failed codewords decoded using the determined LLRs is identified.
    Type: Grant
    Filed: March 14, 2016
    Date of Patent: June 27, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Chandra C. Varanasi, Gerald L. Cadloni
  • Patent number: 9524207
    Abstract: A memory device may include memory components for storing data. The memory device may also include a controller that determines whether one or more errors exist in a data packet stored in the memory components. The controller may read a code word associated with the data packet, such that the code word may be used to indicate whether the errors exist in the data packet. The controller may then determine a syndrome polynomial based on the code word and determine an inverse of the syndrome polynomial when the syndrome polynomial is not zero. The controller may then determine a first error locator polynomial and a second error locator polynomial based on the inverse of the syndrome polynomial. The first error locator polynomial and the second error locator polynomial may be used to identify one or more locations of one or more errors in the code word.
    Type: Grant
    Filed: September 2, 2014
    Date of Patent: December 20, 2016
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20160350184
    Abstract: Embodiments of the present invention disclose methods and apparatuses for correcting errors in data stored in a solid state device. The solid state device may have a plurality of bits stored in multi-level memory cells. The method may include identifying one or more errors in a plurality of memory cells. The method may further include converting the erroneous cells to erasures. The method may further include correcting the one or more erasures.
    Type: Application
    Filed: May 26, 2015
    Publication date: December 1, 2016
    Inventor: CHANDRA C. VARANASI
  • Patent number: 9411529
    Abstract: The present disclosure includes methods and apparatuses for mapping between program states and data patterns. One method includes mapping a data pattern to a number of program state combinations L corresponding to a group of memory cells configured to store a fractional number of data units per cell. The mapping can be based, at least partially, on a recursive expression performed in a number of operations, the number of operations based on a number of memory cells N within the group of memory cells and the number of program state combinations L.
    Type: Grant
    Filed: January 26, 2016
    Date of Patent: August 9, 2016
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi