Patents by Inventor Suresh N. Rajan

Suresh N. Rajan 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: 9575835
    Abstract: A dynamic random access memory (DRAM) array is configured for selective repair and error correction of a subset of the array. Error-correcting code (ECC) is provided to a selected subset of the array to protect a row or partial row of memory cells where one or more weak memory cells are detected. By adding a sense amplifier stripe to the edge of the memory array, the adjacent edge segment of the array is employed to store ECC information associated with the protected subsets of the array. Bit replacement is also applied to defective memory cells. By implementing ECC selectively rather than to the entire array, integrity of the memory array is maintained at minimal cost to the array in terms of area and energy consumption.
    Type: Grant
    Filed: April 21, 2015
    Date of Patent: February 21, 2017
    Assignee: Rambus Inc.
    Inventors: Thomas Vogelsang, Suresh N. Rajan, Ian P. Shaeffer, Frederick A. Ware, Wayne F. Ellis
  • Publication number: 20150234707
    Abstract: A dynamic random access memory (DRAM) array is configured for selective repair and error correction of a subset of the array. Error-correcting code (ECC) is provided to a selected subset of the array to protect a row or partial row of memory cells where one or more weak memory cells are detected. By adding a sense amplifier stripe to the edge of the memory array, the adjacent edge segment of the array is employed to store ECC information associated with the protected subsets of the array. Bit replacement is also applied to defective memory cells. By implementing ECC selectively rather than to the entire array, integrity of the memory array is maintained at minimal cost to the array in terms of area and energy consumption.
    Type: Application
    Filed: April 21, 2015
    Publication date: August 20, 2015
    Inventors: Thomas Vogelsang, Suresh N. Rajan, Ian P. Shaeffer, Frederick A. Ware, Wayne F. Ellis
  • Patent number: 9037949
    Abstract: A dynamic random access memory (DRAM) array is configured for selective repair and error correction of a subset of the array. Error-correcting code (ECC) is provided to a selected subset of the array to protect a row or partial row of memory cells where one or more weak memory cells are detected. By adding a sense amplifier stripe to the edge of the memory array, the adjacent edge segment of the array is employed to store ECC information associated with the protected subsets of the array. Bit replacement is also applied to defective memory cells. By implementing ECC selectively rather than to the entire array, integrity of the memory array is maintained at minimal cost to the array in terms of area and energy consumption.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: May 19, 2015
    Assignee: Rambus Inc.
    Inventors: Thomas Vogelsang, Suresh N. Rajan, Ian P. Shaeffer, Frederick A. Ware, Wayne F. Ellis
  • Patent number: 8619452
    Abstract: Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.
    Type: Grant
    Filed: September 1, 2006
    Date of Patent: December 31, 2013
    Assignee: Google Inc.
    Inventors: Suresh N. Rajan, Michael J. S. Smith, David T Wang
  • Publication number: 20130103896
    Abstract: A memory module, which includes at least one memory stack, comprises a plurality of DRAM integrated circuits and an interface circuit. The interface circuit interfaces the memory stack to a host system so as to operate the memory stack as a single DRAM integrated circuit. In other embodiments, a memory module includes at least one memory stack and a buffer integrated circuit. The buffer integrated circuit, coupled to a host system, interfaces the memory stack to the host system so to operate the memory stack as at least two DRAM integrated circuits. In yet other embodiments, the buffer circuit interfaces the memory stack to the host system for transforming one or more physical parameters between the DRAM integrated circuits and the host system.
    Type: Application
    Filed: September 14, 2012
    Publication date: April 25, 2013
    Applicant: GOOGLE INC.
    Inventors: Suresh N. Rajan, Keith R. Schakel, Michael J.S. Smith, David T. Wang, Frederick Daniel Weber
  • Publication number: 20130100746
    Abstract: Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.
    Type: Application
    Filed: September 14, 2012
    Publication date: April 25, 2013
    Applicant: GOOGLE INC.
    Inventors: Suresh N. Rajan, Michael J. S. Smith, David T. Wang
  • Publication number: 20120268982
    Abstract: Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.
    Type: Application
    Filed: June 28, 2012
    Publication date: October 25, 2012
    Applicant: GOOGLE INC.
    Inventor: Suresh N. Rajan
  • Publication number: 20120102292
    Abstract: A memory module, which includes at least one memory stack, comprises a plurality of DRAM integrated circuits and an interface circuit. The interface circuit interfaces the memory stack to a host system so as to operate the memory stack as a single DRAM integrated circuit. In other embodiments, a memory module includes at least one memory stack and a buffer integrated circuit. The buffer integrated circuit, coupled to a host system, interfaces the memory stack to the host system so to operate the memory stack as at least two DRAM integrated circuits. In yet other embodiments, the buffer circuit interfaces the memory stack to the host system for transforming one or more physical parameters between the DRAM integrated circuits and the host system.
    Type: Application
    Filed: December 30, 2011
    Publication date: April 26, 2012
    Applicant: GOOGLE INC.
    Inventors: Suresh N. Rajan, Keith R. Schakel, Michael J.S. Smith, David T. Wang, Frederick Daniel Weber
  • Patent number: 8089795
    Abstract: A memory module, which includes at least one memory stack, comprises a plurality of DRAM integrated circuits and an interface circuit. The interface circuit interfaces the memory stack to a host system so as to operate the memory stack as a single DRAM integrated circuit. In other embodiments, a memory module includes at least one memory stack and a buffer integrated circuit. The buffer integrated circuit, coupled to a host system, interfaces the memory stack to the host system so to operate the memory stack as at least two DRAM integrated circuits. In yet other embodiments, an interface circuit maps virtual addresses from the host system to physical addresses of the DRAM integrated circuits in a linear manner. In a further embodiment, the interface circuit maps one or more banks of virtual addresses from the host system to a single one of the DRAM integrated circuits.
    Type: Grant
    Filed: February 5, 2007
    Date of Patent: January 3, 2012
    Assignee: Google Inc.
    Inventors: Suresh N. Rajan, Keith R Schakel, Michael J. S. Smith, David T Wang, Frederick Daniel Weber
  • Publication number: 20110310686
    Abstract: A memory device comprises a first and second integrated circuit dies. The first integrated circuit die comprises a memory core as well as a first interface circuit. The first interface circuit permits full access to the memory cells (e.g., reading, writing, activating, pre-charging and refreshing operations to the memory cells). The second integrated circuit die comprises a second interface that interfaces the memory core, via the first interface circuit, an external bus, such as a synchronous interface to an external bus. A technique combines memory core integrated circuit dies with interface integrated circuit dies to configure a memory device. A speed test on the memory core integrated circuit dies is conducted, and the interface integrated circuit die is electrically coupled to the memory core integrated circuit die based on the speed of the memory core integrated circuit die.
    Type: Application
    Filed: June 21, 2011
    Publication date: December 22, 2011
    Applicant: GOOGLE INC.
    Inventor: Suresh N. Rajan
  • Patent number: 7990746
    Abstract: A memory device comprises a first and second integrated circuit dies. The first integrated circuit die comprises a memory core as well as a first interface circuit. The first interface circuit permits full access to the memory cells (e.g., reading, writing, activating, pre-charging and refreshing operations to the memory cells). The second integrated circuit die comprises a second interface that interfaces the memory core, via the first interface circuit, an external bus, such as a synchronous interface to an external bus. A technique combines memory core integrated circuit dies with interface integrated circuit dies to configure a memory device. A speed test on the memory core integrated circuit dies is conducted, and the interface integrated circuit die is electrically coupled to the memory core integrated circuit die based on the speed of the memory core integrated circuit die.
    Type: Grant
    Filed: July 27, 2009
    Date of Patent: August 2, 2011
    Assignee: Google Inc.
    Inventor: Suresh N. Rajan
  • Publication number: 20100020585
    Abstract: Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.
    Type: Application
    Filed: October 6, 2009
    Publication date: January 28, 2010
    Inventor: Suresh N. Rajan
  • Publication number: 20090290442
    Abstract: A memory device comprises a first and second integrated circuit dies. The first integrated circuit die comprises a memory core as well as a first interface circuit. The first interface circuit permits full access to the memory cells (e.g., reading, writing, activating, pre-charging and refreshing operations to the memory cells). The second integrated circuit die comprises a second interface that interfaces the memory core, via the first interface circuit, an external bus, such as a synchronous interface to an external bus. A technique combines memory core integrated circuit dies with interface integrated circuit dies to configure a memory device. A speed test on the memory core integrated circuit dies is conducted, and the interface integrated circuit die is electrically coupled to the memory core integrated circuit die based on the speed of the memory core integrated circuit die.
    Type: Application
    Filed: July 27, 2009
    Publication date: November 26, 2009
    Inventor: Suresh N. Rajan
  • Patent number: 7599205
    Abstract: Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.
    Type: Grant
    Filed: March 25, 2008
    Date of Patent: October 6, 2009
    Assignee: MetaRAM, Inc.
    Inventor: Suresh N. Rajan
  • Patent number: 7515453
    Abstract: A memory device comprises a first and second integrated circuit dies. The first integrated circuit die comprises a memory core as well as a first interface circuit. The first interface circuit permits full access to the memory cells (e.g., reading, writing, activating, pre-charging and refreshing operations to the memory cells). The second integrated circuit die comprises a second interface that interfaces the memory core, via the first interface circuit, an external bus, such as a synchronous interface to an external bus. A technique combines memory core integrated circuit dies with interface integrated circuit dies to configure a memory device. A speed test on the memory core integrated circuit dies is conducted, and the interface integrated circuit die is electrically coupled to the memory core integrated circuit die based on the speed of the memory core integrated circuit die.
    Type: Grant
    Filed: June 23, 2006
    Date of Patent: April 7, 2009
    Assignee: MetaRAM, Inc.
    Inventor: Suresh N. Rajan
  • Publication number: 20080170425
    Abstract: Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.
    Type: Application
    Filed: March 25, 2008
    Publication date: July 17, 2008
    Inventor: Suresh N. Rajan
  • Publication number: 20080126690
    Abstract: A memory module, which includes at least one memory stack, comprises a plurality of DRAM integrated circuits and an interface circuit. The interface circuit interfaces the memory stack to a host system so as to operate the memory stack as a single DRAM integrated circuit. In other embodiments, a memory module includes at least one memory stack and a buffer integrated circuit. The buffer integrated circuit, coupled to a host system, interfaces the memory stack to the host system so to operate the memory stack as at least two DRAM integrated circuits. In yet other embodiments, an interface circuit maps virtual addresses from the host system to physical addresses of the DRAM integrated circuits in a linear manner. In a further embodiment, the interface circuit maps one or more banks of virtual addresses from the host system to a single one of the DRAM integrated circuits.
    Type: Application
    Filed: February 5, 2007
    Publication date: May 29, 2008
    Inventors: Suresh N. Rajan, Frederick Daniel Weber
  • Patent number: 7379316
    Abstract: Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.
    Type: Grant
    Filed: September 1, 2006
    Date of Patent: May 27, 2008
    Assignee: MetaRAM, Inc.
    Inventor: Suresh N. Rajan
  • Publication number: 20070195613
    Abstract: A memory module, which includes at least one memory stack, comprises a plurality of DRAM integrated circuits and an interface circuit. The interface circuit interfaces the memory stack to a host system so as to operate the memory stack as a single DRAM integrated circuit. In other embodiments, a memory module includes at least one memory stack and a buffer integrated circuit. The buffer integrated circuit, coupled to a host system, interfaces the memory stack to the host system so to operate the memory stack as at least two DRAM integrated circuits. In yet other embodiments, an interface circuit maps virtual addresses from the host system to physical addresses of the DRAM integrated circuits in a linear manner. In a further embodiment, the interface circuit maps one or more banks of virtual addresses from the host system to a single one of the DRAM integrated circuits.
    Type: Application
    Filed: February 5, 2007
    Publication date: August 23, 2007
    Inventors: Suresh N. Rajan, Keith R. Schakel, Michael J.S. Smith, David T. Wang, Frederick Daniel Weber
  • Patent number: 5905577
    Abstract: A probe beam is used to sample the waveform on an IC device under test (DUT) during each cycle of a test pattern applied to the DUT. A reference laser beam is also used to sample the DUT. For each cycle of the test pattern, the reference and probe beams sample the DUT at the same physical location, but at displaced times with respect to each other. Each reference measurement is made at a fixed time relative to the test pattern while the probe measurements are scanned through the test-pattern time portion of interest, in the manner normal to equivalent time sampling, to reconstruct the waveform. For each test cycle, the ratio of these two measurements is taken. The fluctuations of these ratios due to noise is greatly reduced as compared to fluctuations of the probe measurements taken alone. Thus, a smaller number of averages is required to reconstruct the waveform.
    Type: Grant
    Filed: March 15, 1997
    Date of Patent: May 18, 1999
    Assignee: Schlumberger Technologies, Inc.
    Inventors: Kenneth R. Wilsher, Suresh N. Rajan, William K. Lo