Patents by Inventor Deepak Raghu

Deepak Raghu 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: 9058881
    Abstract: Multiple bits of data are programmed together to each cell of a segment of a word line while other segments of the same word line are unprogrammed. Subsequently, additional segments are similarly programmed. Data is read from a partially programmed word line (with a mix of programmed and unprogrammed segments) using a single reading scheme.
    Type: Grant
    Filed: December 5, 2013
    Date of Patent: June 16, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Gautam A. Dusija, Chris Avila, Deepak Raghu, Yingda Dong, Man Mui, Alexander Kwok-Tung Mak, Pao-Ling Koh
  • Publication number: 20150162087
    Abstract: In a charge trapping memory, data that would otherwise be likely to remain adjacent to unwritten word lines is written three times, along three immediately adjacent word lines. The middle copy is protected from charge migration on either side and is considered a safe copy for later reading. Dummy data may be programmed along a number of word lines to format a block for good data retention.
    Type: Application
    Filed: December 6, 2013
    Publication date: June 11, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Chris Avila, Gautam A. Dusija, Yingda Dong
  • Publication number: 20150162086
    Abstract: Multiple bits of data are programmed together to each cell of a segment of a word line while other segments of the same word line are unprogrammed. Subsequently, additional segments are similarly programmed. Data is read from a partially programmed word line (with a mix of programmed and unprogrammed segments) using a single reading scheme.
    Type: Application
    Filed: December 5, 2013
    Publication date: June 11, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Gautam A. Dusija, Chris Avila, Deepak Raghu, Yingda Dong, Man Mui, Alexander Kwok-Tung Mak, Pao-Ling Koh
  • Publication number: 20150162088
    Abstract: In a three-dimensional NAND memory in which a block contains multiple separately-selectable sets of strings connected to the same set of bit lines, sets of strings are zoned, and different operating parameters applied to different zones. Operating parameters for a zone are obtained from characterizing a reference set of strings in the zone.
    Type: Application
    Filed: December 10, 2013
    Publication date: June 11, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Gautam A. Dusija, Yingda Dong, Chris Avila, Deepak Raghu, Pao-Ling Koh
  • Patent number: 9036416
    Abstract: Data, normally read using a page-by page read process, can be recovered from memory cells connected to a broken word line by performing a sequential read process. To determine whether a word line is broken, both a page-by page read process and a sequential read process are performed. The results of both read processes are compared. If the number of mismatches between the two read processes is greater than a threshold, it is concluded that there is a broken word line.
    Type: Grant
    Filed: November 13, 2012
    Date of Patent: May 19, 2015
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Nima Mokhlesi, Lanlan Gu, Ashish Pal Singh Ghai, Deepak Raghu
  • Publication number: 20150117099
    Abstract: Layers in a multi-layer memory array are categorized according to likely error rates as predicted from their memory hole diameters. Data to be stored along a word line in a high risk layer is subject to a redundancy operation (e.g. XOR) with data to be stored along a word line in a low risk layer so that the risk of both being bad is low.
    Type: Application
    Filed: May 22, 2014
    Publication date: April 30, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam A. Dusija, Chris Avila, Yingda Dong, Man Mui, Xiying Costa, Pao-Ling Koh
  • Publication number: 20150121157
    Abstract: Layers in a multi-layer memory array are categorized according to likely error rates as predicted from their memory hole diameters. Data to be stored along a word line in a high risk layer is subject to a redundancy operation (e.g. XOR) with data to be stored along a word line in a low risk layer so that the risk of both being bad is low.
    Type: Application
    Filed: October 28, 2013
    Publication date: April 30, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam A. Dusija, Chris Avila, Yingda Dong, Man Mui, Xiying Costa, Pao-Ling Koh
  • Publication number: 20150121156
    Abstract: Memory hole diameter in a three dimensional memory array may be calculated from characteristics that are observed during programming. Suitable operating parameters may be selected for operating a block based on memory hole diameters. Hot counts of blocks may be adjusted according to memory hole size so that blocks that are expected to fail earlier because of small memory holes are more lightly used than blocks with larger memory holes.
    Type: Application
    Filed: October 28, 2013
    Publication date: April 30, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam A. Dusija, Chris Avila, Yingda Dong, Man Mui, Alexander Kwok-Tung Mak, Pao-Ling Koh
  • Patent number: 9015407
    Abstract: In a three-dimensional NAND memory in which a block contains multiple separately-selectable sets of strings connected to the same set of bit lines, sets of strings are zoned, and different operating parameters applied to different zones. Operating parameters for a zone are obtained from characterizing a reference set of strings in the zone.
    Type: Grant
    Filed: May 28, 2014
    Date of Patent: April 21, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Gautam A. Dusija, Yingda Dong, Chris Avila, Deepak Raghu, Pao-Ling Koh
  • Publication number: 20150085574
    Abstract: In a three dimensional NAND memory, increased threshold voltages in back gate transistors may cause program failures, particularly along word lines near back gates. When back gate transistor threshold voltages cannot be returned to a desired threshold voltage range then modified program conditions, including increased back gate voltage, may be used to allow programming.
    Type: Application
    Filed: September 20, 2013
    Publication date: March 26, 2015
    Applicant: SanDisk Technology Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui
  • Publication number: 20150063028
    Abstract: When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.
    Type: Application
    Filed: May 29, 2014
    Publication date: March 5, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui
  • Publication number: 20150067419
    Abstract: When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.
    Type: Application
    Filed: September 3, 2013
    Publication date: March 5, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, GAUTAM ASHOK DUSIJA, CHRIS NGA YEE AVILA, YINGDA DONG, MAN LUNG MUI
  • Patent number: 8964467
    Abstract: Multiple bits of data are programmed together to each cell of a segment of a word line while other segments of the same word line are unprogrammed. Subsequently, additional segments are similarly programmed. Data is read from a partially programmed word line (with a mix of programmed and unprogrammed segments) using a single reading scheme.
    Type: Grant
    Filed: May 22, 2014
    Date of Patent: February 24, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Gautam A. Dusija, Chris Avila, Deepak Raghu, Yingda Dong, Man Mui, Alexander Kwok-Tung Mak, Pao-Ling Koh
  • Patent number: 8966330
    Abstract: When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.
    Type: Grant
    Filed: May 29, 2014
    Date of Patent: February 24, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui
  • Patent number: 8929141
    Abstract: Erasing memory cells in certain 3-D NAND charge-storage memory arrays is achieved by rapidly charging vertical conductors using Gate Induced Drain Leakage (GIDL) current generated in select transistors. When bit line voltage drops below its nominal value, select line voltage is controlled to maintain a constant voltage difference between bit line voltage and select line voltage thus maintaining a gate-drain voltage difference in select transistors that provides sufficient GIDL current for erase.
    Type: Grant
    Filed: October 2, 2013
    Date of Patent: January 6, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui, Pao-Ling Koh
  • Patent number: 8902661
    Abstract: Memory hole diameter in a three dimensional memory array may be calculated from characteristics that are observed during programming. Suitable operating parameters may be selected for operating a block based on memory hole diameters. Hot counts of blocks may be adjusted according to memory hole size so that blocks that are expected to fail earlier because of small memory holes are more lightly used than blocks with larger memory holes.
    Type: Grant
    Filed: May 21, 2014
    Date of Patent: December 2, 2014
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam A. Dusija, Chris Avila, Yingda Dong, Man Mui, Alexander Kwok-Tung Mak, Pao-Ling Koh
  • Patent number: 8902658
    Abstract: Erasing memory cells in certain 3-D NAND charge-storage memory arrays is achieved by rapidly charging vertical conductors using Gate Induced Drain Leakage (GIDL) current generated in select transistors. When bit line voltage drops below its nominal value, select line voltage is controlled to maintain a constant voltage difference between bit line voltage and select line voltage thus maintaining a gate-drain voltage difference in select transistors that provides sufficient GIDL current for erase.
    Type: Grant
    Filed: May 21, 2014
    Date of Patent: December 2, 2014
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui, Pao-Ling Koh
  • Patent number: 8902647
    Abstract: In a charge trapping memory, data that would otherwise be likely to remain adjacent to unwritten word lines is written three times, along three immediately adjacent word lines. The middle copy is protected from charge migration on either side and is considered a safe copy for later reading. Dummy data may be programmed along a number of word lines to format a block for good data retention.
    Type: Grant
    Filed: May 28, 2014
    Date of Patent: December 2, 2014
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Chris Avila, Gautam A. Dusija, Yingda Dong
  • Patent number: 8886877
    Abstract: In a nonvolatile memory, hybrid blocks are initially written with only lower page data. The hybrid blocks later have middle and upper page data written. For high speed writes, data is written to a hybrid block and two or more Single Level Cell (SLC) blocks. The data from the SLC blocks are copied to the hybrid block at a later time in a folding operation.
    Type: Grant
    Filed: May 15, 2014
    Date of Patent: November 11, 2014
    Assignee: SanDisk Technologies Inc.
    Inventors: Chris Avila, Gautam Dusija, Deepak Raghu, Cynthia Hsu, Changyuan Chen, Farookh Moogat
  • Patent number: 8756024
    Abstract: An energy analysis system provides valuable input into building energy expenditures. The system assists with obtaining a detailed view of how energy consumption occurs in a building, what steps may be taken to lower the energy footprint, and executing detailed energy consumption analysis. The analysis may include, as examples, a balance point pair analysis to determine either or both of a heating balance point and a cooling balance point, an exception rank analysis to identify specific data (e.g., energy consumption data) in specific time intervals for further review, or other analysis. The system may display the analysis results on a user interface.
    Type: Grant
    Filed: May 7, 2010
    Date of Patent: June 17, 2014
    Assignee: Accenture Global Services Limited
    Inventors: Jay Hedley, Boris Tsypin, Deepak Raghu