Patents by Inventor C. Varanasi

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: 9405622
    Abstract: Apparatuses and methods associated with shaping codes for memory are provided. One example apparatus comprises an array of memory cells and a shaping component coupled to the array and configured to encode each of a number of received digit patterns according to a mapping of received digit patterns to shaping digit patterns. The mapping of received digit patterns to shaping digit patterns obeys a shaping constraint that limits, to an uppermost amount, an amount of consecutive digits of the shaping digit patterns allowed to have a particular digit value.
    Type: Grant
    Filed: March 10, 2015
    Date of Patent: August 2, 2016
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20160197623
    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: March 14, 2016
    Publication date: July 7, 2016
    Inventors: Chandra C. Varanasi, Gerald L. Cadloni
  • Publication number: 20160139848
    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: Application
    Filed: January 26, 2016
    Publication date: May 19, 2016
    Inventor: Chandra C. Varanasi
  • Patent number: 9306600
    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: January 6, 2014
    Date of Patent: April 5, 2016
    Assignee: Micron Technology, Inc.
    Inventors: Chandra C. Varanasi, Gerald L. Cadloni
  • Patent number: 9280456
    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: November 12, 2013
    Date of Patent: March 8, 2016
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20160062826
    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: Application
    Filed: September 2, 2014
    Publication date: March 3, 2016
    Inventor: Chandra C. Varanasi
  • Patent number: 9251000
    Abstract: Methods and apparatuses for combining error coding and modulation schemes are described herein. One or more methods include encoding data using linear error correcting code, modulating the encoded data, writing the modulated data to memory, and decoding the written data using a Viterbi algorithm and a linear error correcting code decoder.
    Type: Grant
    Filed: October 28, 2014
    Date of Patent: February 2, 2016
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Patent number: 9170877
    Abstract: Apparatuses and methods for resolving trapping sets are provided. One example method can include attempting to decode a codeword using initial values for confidence levels associated with digits of the codeword. For a trapping set, the confidence levels associated with the digits corresponding to a failed parity check are adjusted. The method further includes attempting to decode a codeword using the adjusted value for the confidence levels of the digits corresponding to the failed parity check.
    Type: Grant
    Filed: January 21, 2014
    Date of Patent: October 27, 2015
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Patent number: 9105350
    Abstract: Methods of operating an apparatus such as a computing system and/or memory device for memory endurance are provided. One example method can include receiving m digits of data having a first quantity of digits represented by a first data state that is more detrimental to memory cell wear than a second data state. The m digits of data are encoded into n digits of data having a second quantity of digits represented by the first data state. The value n is greater than the value m. The second quantity is less than or equal to the first quantity. The n digits of data are stored in an apparatus having memory cells.
    Type: Grant
    Filed: May 22, 2014
    Date of Patent: August 11, 2015
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20150194983
    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: January 6, 2014
    Publication date: July 9, 2015
    Applicant: Micron Technology, Inc.
    Inventors: Chandra C. Varanasi, Gerald L. Cadloni
  • Publication number: 20150178158
    Abstract: Apparatuses and methods associated with shaping codes for memory are provided. One example apparatus comprises an array of memory cells and a shaping component coupled to the array and configured to encode each of a number of received digit patterns according to a mapping of received digit patterns to shaping digit patterns. The mapping of received digit patterns to shaping digit patterns obeys a shaping constraint that limits, to an uppermost amount, an amount of consecutive digits of the shaping digit patterns allowed to have a particular digit value.
    Type: Application
    Filed: March 10, 2015
    Publication date: June 25, 2015
    Inventor: Chandra C. Varanasi
  • Publication number: 20150134927
    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: Application
    Filed: November 12, 2013
    Publication date: May 14, 2015
    Applicant: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Patent number: 9030902
    Abstract: Methods for programming memory cells. One such method for programming memory cells includes generating an encoded stream using a data stream and programming the memory cells using the encoded stream to represent the data stream. A particular bit position of the encoded stream has a first voltage level when the particular bit position of the data stream has a particular logical state, and the particular bit position of the encoded stream has either a second voltage level or a third voltage level when the particular bit position of the data stream has a logical state other than the particular logical state.
    Type: Grant
    Filed: July 14, 2014
    Date of Patent: May 12, 2015
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Patent number: 8984369
    Abstract: Apparatuses and methods associated with shaping codes for memory are provided. One example apparatus comprises an array of memory cells and a shaping component coupled to the array and configured to encode each of a number of received digit patterns according to a mapping of received digit patterns to shaping digit patterns. The mapping of received digit patterns to shaping digit patterns obeys a shaping constraint that limits, to an uppermost amount, an amount of consecutive digits of the shaping digit patterns allowed to have a particular digit value.
    Type: Grant
    Filed: November 21, 2012
    Date of Patent: March 17, 2015
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20150074498
    Abstract: Methods and apparatuses for combining error coding and modulation schemes are described herein. One or more methods include encoding data using linear error correcting code, modulating the encoded data, writing the modulated data to memory, and decoding the written data using a Viterbi algorithm and a linear error correcting code decoder.
    Type: Application
    Filed: October 28, 2014
    Publication date: March 12, 2015
    Inventor: Chandra C. Varanasi
  • Publication number: 20150039960
    Abstract: Some embodiments include apparatus and methods for encoding message information. Such apparatus and methods can include using a parity check matrix of a low-density parity check (LDPC) code to generate a first matrix having an upper triangular sub-matrix. Parity information to encode the message information can be generated based on the first matrix if a total number of rows of the upper triangular sub-matrix is equal to the rank of the parity check matrix. If the total number of rows of the upper triangular sub-matrix is less than the rank of the parity check matrix, then a triangularization operation can be performed on a second sub-matrix of the first matrix to generate a second matrix. Parity information to encode the message information can be generated based on the second matrix. Other embodiments including additional apparatus and methods are described.
    Type: Application
    Filed: September 15, 2014
    Publication date: February 5, 2015
    Inventors: Chandra C. Varanasi, Guiqiang Dong
  • Patent number: 8892986
    Abstract: Methods and apparatuses for combining error coding and modulation schemes are described herein. One or more methods include encoding data using linear error correcting code, modulating the encoded data, writing the modulated data to memory, and decoding the written data using a Viterbi algorithm and a linear error correcting code decoder.
    Type: Grant
    Filed: March 8, 2012
    Date of Patent: November 18, 2014
    Assignee: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20140337564
    Abstract: Methods of operating an apparatus such as a computing system and/or memory device for memory endurance are provided. One example method can include receiving m digits of data having a first quantity of digits represented by a first data state that is more detrimental to memory cell wear than a second data state. The m digits of data are encoded into n digits of data having a second quantity of digits represented by the first data state. The value n is greater than the value m. The second quantity is less than or equal to the first quantity. The n digits of data are stored in an apparatus having memory cells.
    Type: Application
    Filed: May 22, 2014
    Publication date: November 13, 2014
    Applicant: Micron Technology, Inc.
    Inventor: Chandra C. Varanasi
  • Publication number: 20140321214
    Abstract: Methods for programming memory cells. One such method for programming memory cells includes generating an encoded stream using a data stream and programming the memory cells using the encoded stream to represent the data stream. A particular bit position of the encoded stream has a first voltage level when the particular bit position of the data stream has a particular logical state, and the particular bit position of the encoded stream has either a second voltage level or a third voltage level when the particular bit position of the data stream has a logical state other than the particular logical state.
    Type: Application
    Filed: July 14, 2014
    Publication date: October 30, 2014
    Applicant: MICRON TECHNOLOGY, INC.
    Inventor: Chandra C. Varanasi
  • Patent number: 8839069
    Abstract: Some embodiments include apparatus and methods for encoding message information. Such apparatus and methods can include using a parity check matrix of a low-density parity check (LDPC) code to generate a first matrix having an upper triangular sub-matrix. Parity information to encode the message information can be generated based on the first matrix if a total number of rows of the upper triangular sub-matrix is equal to the rank of the parity check matrix. If the total number of rows of the upper triangular sub-matrix is less than the rank of the parity check matrix, then a triangularization operation can be performed on a second sub-matrix of the first matrix to generate a second matrix. Parity information to encode the message information can be generated based on the second matrix. Other embodiments including additional apparatus and methods are described.
    Type: Grant
    Filed: April 8, 2011
    Date of Patent: September 16, 2014
    Assignee: Micron Technology, Inc.
    Inventors: Chandra C. Varanasi, Guiqiang Dong