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).
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Patent number: 11243838Abstract: 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: GrantFiled: May 14, 2020Date of Patent: February 8, 2022Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Publication number: 20200272539Abstract: 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: ApplicationFiled: May 14, 2020Publication date: August 27, 2020Applicant: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Patent number: 10706897Abstract: 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: GrantFiled: July 2, 2019Date of Patent: July 7, 2020Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Patent number: 10691538Abstract: 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: GrantFiled: September 25, 2018Date of Patent: June 23, 2020Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Publication number: 20190325921Abstract: 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: ApplicationFiled: July 2, 2019Publication date: October 24, 2019Inventor: Chandra C. Varanasi
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Patent number: 10354700Abstract: 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: GrantFiled: August 23, 2018Date of Patent: July 16, 2019Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Publication number: 20190026182Abstract: 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: ApplicationFiled: September 25, 2018Publication date: January 24, 2019Applicant: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Publication number: 20180366164Abstract: 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: ApplicationFiled: August 23, 2018Publication date: December 20, 2018Inventor: Chandra C. Varanasi
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Patent number: 10121521Abstract: 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: GrantFiled: December 11, 2017Date of Patent: November 6, 2018Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Patent number: 10120753Abstract: 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: GrantFiled: May 26, 2015Date of Patent: November 6, 2018Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Patent number: 9985651Abstract: 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: GrantFiled: May 25, 2017Date of Patent: May 29, 2018Assignee: Micron Technology, Inc.Inventors: Chandra C. Varanasi, Gerald L. Cadloni
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Publication number: 20180102146Abstract: 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: ApplicationFiled: December 11, 2017Publication date: April 12, 2018Inventor: Chandra C. Varanasi
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Patent number: 9911466Abstract: 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: GrantFiled: February 16, 2016Date of Patent: March 6, 2018Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Publication number: 20170264312Abstract: 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: ApplicationFiled: May 25, 2017Publication date: September 14, 2017Inventors: Chandra C. Varanasi, Gerald L. Cadloni
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Publication number: 20170236562Abstract: 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: ApplicationFiled: February 16, 2016Publication date: August 17, 2017Inventor: Chandra C. Varanasi
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Patent number: 9697892Abstract: 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 āiā being a whole number index from 1 to X?1.Type: GrantFiled: October 4, 2016Date of Patent: July 4, 2017Assignee: Micron Technology, Inc.Inventors: Chandra C. Varanasi, Bruce A. Liikanen
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Patent number: 9692449Abstract: 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: GrantFiled: March 14, 2016Date of Patent: June 27, 2017Assignee: Micron Technology, Inc.Inventors: Chandra C. Varanasi, Gerald L. Cadloni
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Patent number: 9524207Abstract: 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: GrantFiled: September 2, 2014Date of Patent: December 20, 2016Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi
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Publication number: 20160350184Abstract: 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: ApplicationFiled: May 26, 2015Publication date: December 1, 2016Inventor: CHANDRA C. VARANASI
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Patent number: 9411529Abstract: 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: GrantFiled: January 26, 2016Date of Patent: August 9, 2016Assignee: Micron Technology, Inc.Inventor: Chandra C. Varanasi