Patents by Inventor Anurag Nigam

Anurag Nigam 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: 10290332
    Abstract: A system may include a controller, a data receiving circuit, and a plurality of banks. The banks may send data to the data receiving circuit via a common data bus. The controller may control the communication of the data to the receiving circuit by sending control signals and clock signals to the banks. Relative lengths of control signal paths and clock signal paths may be directly related to each other and inversely related to relative lengths of data paths.
    Type: Grant
    Filed: October 31, 2017
    Date of Patent: May 14, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Yukeun Sim, Anurag Nigam, Yingchang Chen
  • Publication number: 20190130946
    Abstract: A system may include a controller, a data receiving circuit, and a plurality of banks. The banks may send data to the data receiving circuit via a common data bus. The controller may control the communication of the data to the receiving circuit by sending control signals and clock signals to the banks. Relative lengths of control signal paths and clock signal paths may be directly related to each other and inversely related to relative lengths of data paths.
    Type: Application
    Filed: October 31, 2017
    Publication date: May 2, 2019
    Inventors: Yukeun Sim, Anurag Nigam, Yingchang Chen
  • Patent number: 10269444
    Abstract: Techniques and memory devices are provided in which bit line short circuits are detected and groups of bit lines are masked off. A process tests groups of bit lines which are connected to a sense circuit. A masking latch is provided to store test results for each group of bit lines. Once the testing of a group is completed, the test result is communicated to a controller. Moreover, the same masking latch can store and communicate test results for multiple groups of bit lines which are connected to a sense circuit. In a user mode, a masking latch stores masking data for each group of bit lines. In response to a power on reset, the masking data is loaded into the masking latches and remains there over multiple write and read operation, until a next power on reset occurs.
    Type: Grant
    Filed: April 19, 2017
    Date of Patent: April 23, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Anurag Nigam, Yukeun Sim, Jingwen Ouyang, Yingchang Chen
  • Publication number: 20180174668
    Abstract: Techniques and memory devices are provided in which bit line short circuits are detected and groups of bit lines are masked off. A process tests groups of bit lines which are connected to a sense circuit. A masking latch is provided to store test results for each group of bit lines. Once the testing of a group is completed, the test result is communicated to a controller. Moreover, the same masking latch can store and communicate test results for multiple groups of bit lines which are connected to a sense circuit. In a user mode, a masking latch stores masking data for each group of bit lines. In response to a power on reset, the masking data is loaded into the masking latches and remains there over multiple write and read operation, until a next power on reset occurs.
    Type: Application
    Filed: April 19, 2017
    Publication date: June 21, 2018
    Applicant: SanDisk Technologies LLC
    Inventors: Anurag Nigam, Yukeun Sim, Jingwen Ouyang, Yingchang Chen
  • Patent number: 9704572
    Abstract: A non-volatile memory is described that includes a sense amplifier that maintains a bit line voltage and output of the sense amplifier at a substantially constant voltage during read operations. During a preset phase, an output of the sense amplifier that is coupled to a selected bit line is grounded. At least one capacitor is precharged during the preset phase. During a sense phase, the sense amplifier output is disconnected from ground while the memory array is biased for reading a selected memory cell. A resulting cell current is integrated by the at least one capacitor. The integrated cell current discharges a sense node from the precharge level to an accurate voltage level based on the resulting cell current.
    Type: Grant
    Filed: March 20, 2015
    Date of Patent: July 11, 2017
    Assignee: SanDisk Technologies LLC
    Inventors: Yingchang Chen, Anurag Nigam, Chang Siau
  • Patent number: 9595323
    Abstract: A method is provided for operating a non-volatile storage system that includes a plurality of bit lines, a word line comb including a plurality of word lines, and a plurality of memory elements, each memory element coupled between one of the bit lines and one of the word lines. The method includes receiving a current conducted by the word line comb, estimating a resistance of a conductive path between the word line comb and a selected word line voltage node, and generating a voltage at the selected word line voltage node based on the received current and the estimated resistance so that a voltage of the word line comb substantially equals a reference voltage.
    Type: Grant
    Filed: February 4, 2016
    Date of Patent: March 14, 2017
    Assignee: SanDisk Technologies LLC
    Inventors: Yingchang Chen, Jeffrey Koonyee Lee, Chang Siau, Anurag Nigam, Thomas Yan
  • Publication number: 20160276023
    Abstract: A non-volatile memory is described that includes a sense amplifier that maintains a bit line voltage and output of the sense amplifier at a substantially constant voltage during read operations. During a preset phase, an output of the sense amplifier that is coupled to a selected bit line is grounded. At least one capacitor is precharged during the preset phase. During a sense phase, the sense amplifier output is disconnected from ground while the memory array is biased for reading a selected memory cell. A resulting cell current is integrated by the at least one capacitor. The integrated cell current discharges a sense node from the precharge level to an accurate voltage level based on the resulting cell current.
    Type: Application
    Filed: March 20, 2015
    Publication date: September 22, 2016
    Applicant: SANDISK 3D LLC
    Inventors: Yingchang Chen, Anurag Nigam, Chang Siau
  • Patent number: 9390793
    Abstract: A non-volatile memory includes a sense amplifier that uses a reference bit line. The sense amplifier includes a first capacitor coupled to a selected bit line and a second capacitor coupled to a reference bit line. The reference capacitor compensates for displacement currents in the selected bit line during sensing. Both plates of the capacitors are utilized to cancel leakage currents. The top plates of the capacitors are precharged then discharged during a sense phase. The selected bit line capacitor is discharged based on the selected cell current and the leakage current. The amount of discharge is transferred to the bottom plate of each capacitor, followed by discharging the bottom plates. The capacitor for the selected bit line is discharged based on the leakage current. In this manner, the correction phase facilitates a compensation based on the leakage current so that the selected cell current can be determined.
    Type: Grant
    Filed: March 20, 2015
    Date of Patent: July 12, 2016
    Assignee: SanDisk Technologies LLC
    Inventors: Anurag Nigam, Yingchang Chen
  • Publication number: 20160042771
    Abstract: Methods for determining memory cell states during a read operation using a detection scheme that reduces the area of detection circuitry for detecting the states of the memory cells by time multiplexing the use of portions of the detection circuitry are described. The read operation may include a precharge phase, a sensing phase, and a detection phase. In some embodiments, a first bit line and a second bit line may be precharged to a read voltage in parallel, and then sensing and/or detection of selected memory cells corresponding with the first bit line and the second bit line may be performed serially using the same detection circuitry by time multiplexing the use of the detection circuitry. In some cases, the time multiplexed detection circuitry may be used for detecting two or more states corresponding with two or more memory cells being sensed during a read operation.
    Type: Application
    Filed: October 20, 2015
    Publication date: February 11, 2016
    Applicant: SANDISK 3D LLC
    Inventors: Anurag Nigam, Gopinath Balakrishnan
  • Patent number: 9245599
    Abstract: Methods for determining memory cell states during a read operation using a detection scheme that reduces the area of detection circuitry for detecting the states of the memory cells by time multiplexing the use of portions of the detection circuitry are described. The read operation may include a precharge phase, a sensing phase, and a detection phase. In some embodiments, a first bit line and a second bit line may be precharged to a read voltage in parallel, and then sensing and/or detection of selected memory cells corresponding with the first bit line and the second bit line may be performed serially using the same detection circuitry by time multiplexing the use of the detection circuitry. In some cases, the time multiplexed detection circuitry may be used for detecting two or more states corresponding with two or more memory cells being sensed during a read operation.
    Type: Grant
    Filed: October 20, 2015
    Date of Patent: January 26, 2016
    Assignee: SANDISK 3D LLC
    Inventors: Anurag Nigam, Gopinath Balakrishnan
  • Patent number: 9224466
    Abstract: Methods and apparatus are provided for reading a selected memory cell of a memory array using a sense amplifier that includes a first capacitor and a second capacitor. The selected memory cell is coupled to a bit line and a selected word line. A first noise voltage is generated on the first capacitor, and a selected memory cell voltage and a second noise voltage are generated on the second capacitor. The first noise voltage is an estimate of the second noise voltage. An output signal value is generated proportional to a difference between the selected memory cell voltage and a reference voltage, and a difference between the first noise voltage and second noise voltage. The output signal value is used to determine a data value for the selected memory cell.
    Type: Grant
    Filed: September 29, 2014
    Date of Patent: December 29, 2015
    Assignee: SanDisk 3D LLC
    Inventors: Yingchang Chen, Anurag Nigam
  • Patent number: 9196373
    Abstract: Methods for determining memory cell states during a read operation using a detection scheme that reduces the area of detection circuitry for detecting the states of the memory cells by time multiplexing the use of portions of the detection circuitry are described. The read operation may include a precharge phase, a sensing phase, and a detection phase. In some embodiments, a first bit line and a second bit line may be precharged to a read voltage in parallel, and then sensing and/or detection of selected memory cells corresponding with the first bit line and the second bit line may be performed serially using the same detection circuitry by time multiplexing the use of the detection circuitry. In some cases, the time multiplexed detection circuitry may be used for detecting two or more states corresponding with two or more memory cells being sensed during a read operation.
    Type: Grant
    Filed: February 26, 2014
    Date of Patent: November 24, 2015
    Assignee: SANDISK 3D LLC
    Inventors: Anurag Nigam, Gopinath Balakrishnan
  • Publication number: 20150243362
    Abstract: Methods for determining memory cell states during a read operation using a detection scheme that reduces the area of detection circuitry for detecting the states of the memory cells by time multiplexing the use of portions of the detection circuitry are described. The read operation may include a precharge phase, a sensing phase, and a detection phase. In some embodiments, a first bit line and a second bit line may be precharged to a read voltage in parallel, and then sensing and/or detection of selected memory cells corresponding with the first bit line and the second bit line may be performed serially using the same detection circuitry by time multiplexing the use of the detection circuitry. In some cases, the time multiplexed detection circuitry may be used for detecting two or more states corresponding with two or more memory cells being sensed during a read operation.
    Type: Application
    Filed: February 26, 2014
    Publication date: August 27, 2015
    Applicant: SANDISK 3D LLC
    Inventors: Anurag Nigam, Gopinath Balakrishnan
  • Patent number: 7460554
    Abstract: A method and apparatus for the incorporation of any size and location of concatenated SONET frames, which carry packet data, in an SONET signal are described. In an embodiment, a method includes receiving packet data. Additionally, the method includes concatenating the packet data into a Time Division Multiplexing (TDM) Synchronous Optical Network (SONET) signal. The concatenation can be across any locations within the TDM SONET signal, and a size of the concatenation can be in increments of single SONET frames. The method also includes transmitting the TDM SONET signal having the concatenated packet data.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: December 2, 2008
    Assignee: Redback Networks Inc.
    Inventors: Anurag Nigam, David Stiles
  • Patent number: 7277447
    Abstract: An on-chip RAM FIFO (first-in-first-out) buffer for storing SPE overhead bytes wherein each entry of the RAM FIFO stores (1) a byte of the SPE overhead; (2) an indication of which byte of the SPE overhead is currently stored in that entry; and (3) an indication of which STS signal that byte was taken from.
    Type: Grant
    Filed: March 30, 2001
    Date of Patent: October 2, 2007
    Assignee: Redback Networks Inc.
    Inventors: James Wang, Anurag Nigam, David R. Stiles
  • Patent number: 7272157
    Abstract: A method and apparatus for the incorporation of any size and location of concatenated SONET frames, which carry packet data, in an SONET signal are described. In an embodiment, a method includes receiving packet data. Additionally, the method includes concatenating the packet data into a Time Division Multiplexing (TDM) Synchronous Optical Network (SONET) signal. The concatenation can be across any locations within the TDM SONET signal, and a size of the concatenation can be in increments of single SONET frames. The method also includes transmitting the TDM SONET signal having the concatenated packet data.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: September 18, 2007
    Assignee: Redback Networks Inc.
    Inventors: Anurag Nigam, David Stiles
  • Patent number: 7165200
    Abstract: A system and method are disclosed for characterizing a signal path. The system includes a system clock configured to produce a system clock signal at a sample frequency. A frequency divider is configured to divide the sample frequency of the system clock signal by a factor of N to produce a chip clock signal at a chip frequency. The system further includes a pseudo-noise (PN) sequence generator configured to produce a PN sequence at the chip frequency and couple the PN sequence to the signal path while the signal path is carrying an operational signal. A sub-chip sampler is configured to correlate the PN sequence and a reflected PN sequence which has been reflected within the signal path to form a correlated signal and to sample the correlated signal at the sample frequency of the system clock signal.
    Type: Grant
    Filed: May 5, 2005
    Date of Patent: January 16, 2007
    Assignee: University of Utah Research Foundation
    Inventors: Nilay D. Jani, Anurag Nigam, Cynthia M. Furse
  • Patent number: 6993047
    Abstract: Any size and location of concatenated packet data across Synchronous Optical Network (SONET) frames in a SONET signal is provided. In one embodiment, a method may include receiving portions of packets and placing the portions into buffers. Additionally, the method may determine packet boundaries among the portions of packets in the buffers to locate a number of packets. Additionally, the method may concatenate the packet data into a Time Division Multiplexing (TDM) SONET signal. The concatenation can be across any locations within the TDM SONET signal, and the size of the concatenation can be in increments of single SONET frames. In another embodiment, the number of packets may be concatenated within locations in the TDM SONET signal not occupied by the TDM data traffic. In one embodiment, the TDM SONET signal having the concatenated packet data may be transmitted.
    Type: Grant
    Filed: December 30, 2000
    Date of Patent: January 31, 2006
    Assignee: Redback Networks Inc.
    Inventors: Anurag Nigam, David Stiles
  • Publication number: 20050289408
    Abstract: A system and method are disclosed for characterizing a signal path. The system includes a system clock configured to produce a system clock signal at a sample frequency. A frequency divider is configured to divide the sample frequency of the system clock signal by a factor of N to produce a chip clock signal at a chip frequency. The system further includes a pseudo-noise (PN) sequence generator configured to produce a PN sequence at the chip frequency and couple the PN sequence to the signal path while the signal path is carrying an operational signal. A sub-chip sampler is configured to correlate the PN sequence and a reflected PN sequence which has been reflected within the signal path to form a correlated signal and to sample the correlated signal at the sample frequency of the system clock signal.
    Type: Application
    Filed: May 5, 2005
    Publication date: December 29, 2005
    Inventors: Nilay Jani, Anurag Nigam, Cynthia Furse
  • Publication number: 20050135436
    Abstract: A method and apparatus for the incorporation of any size and location of concatenated SONET frames, which carry packet data, in an SONET signal are described. In an embodiment, a method includes receiving packet data. Additionally, the method includes concatenating the packet data into a Time Division Multiplexing (TDM) Synchronous Optical Network (SONET) signal. The concatenation can be across any locations within the TDM SONET signal, and a size of the concatenation can be in increments of single SONET frames. The method also includes transmitting the TDM SONET signal having the concatenated packet data.
    Type: Application
    Filed: January 14, 2005
    Publication date: June 23, 2005
    Inventors: Anurag Nigam, David Stiles