Patents by Inventor Elizabeth Lair Gerhard

Elizabeth Lair Gerhard 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: 8331180
    Abstract: A static random access memory (SRAM) includes an SRAM cell to store a bit of data. A word line accesses the SRAM cell, which, responsively, during a read, drives either a bit line true (BLT) or a bit line complement (BLC) low. Both BLT and BLC are precharged to a supply voltage, then, subsequently are discharged to a reference voltage, lower than the supply voltage, prior to the word line being activated. Because the bit lines are at a voltage lower than the supply voltage when the SRAM cell is activated, the SRAM cell stability is improved.
    Type: Grant
    Filed: September 30, 2010
    Date of Patent: December 11, 2012
    Assignee: International Business Machines Corporation
    Inventors: Chad Allen Adams, Sharon Huertas Cesky, Elizabeth Lair Gerhard, Jeffrey Milton Scherer
  • Patent number: 8213249
    Abstract: A method and static random access memory (SRAM) circuit for implementing low power data predicting local evaluation for double pumped arrays, and a design structure on which the subject circuit reside are provided. A novel variation of a domino read local evaluation circuit accurately predicts the write data for the next cycle. The domino read local evaluation circuit uses static write data set up prior to a write enable signal to determine the value of the data that is being written into the array. When the data being written to the array matches the data last read the local bitlines stay in their previous state. When the data being written is opposite of the data last read then the bit lines are precharged to the precharge value.
    Type: Grant
    Filed: May 27, 2010
    Date of Patent: July 3, 2012
    Assignee: International Business Machines Corporation
    Inventors: Chad Allen Adams, Sharon Huertas Cesky, Elizabeth Lair Gerhard, Jeffrey Milton Scherer
  • Publication number: 20120081949
    Abstract: A static random access memory (SRAM) includes an SRAM cell to store a bit of data. A word line accesses the SRAM cell, which, responsively, during a read, drives either a bit line true (BLT) or a bit line complement (BLC) low. Both BLT and BLC are precharged to a supply voltage, then, subsequently are discharged to a reference voltage, lower than the supply voltage, prior to the word line being activated. Because the bit lines are at a voltage lower than the supply voltage when the SRAM cell is activated, the SRAM cell stability is improved.
    Type: Application
    Filed: September 30, 2010
    Publication date: April 5, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Chad Allen Adams, Sharon Huertas Cesky, Elizabeth Lair Gerhard, Jeffrey Milton Scherer
  • Publication number: 20110292748
    Abstract: A method and static random access memory (SRAM) circuit for implementing low power data predicting local evaluation for double pumped arrays, and a design structure on which the subject circuit reside are provided. A novel variation of a domino read local evaluation circuit accurately predicts the write data for the next cycle. The domino read local evaluation circuit uses static write data set up prior to a write enable signal to determine the value of the data that is being written into the array. When the data being written to the array matches the data last read the local bitlines stay in their previous state. When the data being written is opposite of the data last read then the bit lines are precharged to the precharge value.
    Type: Application
    Filed: May 27, 2010
    Publication date: December 1, 2011
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Chad Allen Adams, Sharon Huertas Cesky, Elizabeth Lair Gerhard, Jeffrey Milton Scherer
  • Patent number: 7783943
    Abstract: A method and apparatus for testing a random access memory device is provided. One embodiment involves providing an interface between Logic Built in Self Test (LBIST) and Array Built in Self Test (ABIST) paths for memory testing, including providing a cross-coupled NAND device with an LBIST test path; configuring the cross-coupled NAND device for interfacing ABIST and LBIST paths by modeling a worst case scenario for timing from a domino read static random access memory (SRAM) array; and modifying data in the cross-coupled NAND device using an LBIST controlled data path at essentially the latest point in time when a read may propagate from the array to provide full AC test coverage of down stream logic.
    Type: Grant
    Filed: May 15, 2008
    Date of Patent: August 24, 2010
    Assignee: International Business Machines Corporation
    Inventors: Chad Allen Adams, Elizabeth Lair Gerhard, Sharon Huertas Cesky, Jeffrey Milton Scherer
  • Patent number: 7715221
    Abstract: A method and apparatus implementing domino static random access memory (SRAM) leakage current reduction include a local evaluation circuit coupled to true and complement bit lines of a pair of local SRAM cell groups, receives precharge signals and provides an output connected to a global dot line. A sleep input is applied to SRAM sleep logic and a write driver including sleep control. Data true and data complement outputs of the write driver are forced to a respective selected level to discharge the bit lines and global dot lines when the sleep input transitions high. Discharging the bit lines and global dot lines is implemented through gating in the write driver without requiring any additional devices in the local evaluation circuit.
    Type: Grant
    Filed: June 23, 2008
    Date of Patent: May 11, 2010
    Assignee: International Business Machines Corporation
    Inventors: Todd Alan Christensen, Elizabeth Lair Gerhard, Omer Heymann, Amira Rozenfeld
  • Publication number: 20090285039
    Abstract: A method and apparatus for write assist for a static random access memory (SRAM) array, is provided, which increases the write ability of the SRAM cell by locally raising the source voltage. One embodiment involves locally generating a virtual ground for write assist on column selected SRAM cells, including locally raising the source voltage to increase the write ability of the SRAM cell; wherein locally raising the source voltage comprises locally generating a virtual source/ground node for boosting the write ability of a column of SRAM cells without using an additional on-chip or off-chip supply; thereby decreasing the voltage differential across the source and supply of the column of SRAM cells during a write, and restoring the standard chip differential during a read.
    Type: Application
    Filed: May 15, 2008
    Publication date: November 19, 2009
    Applicant: International Business Machines Corporation
    Inventors: Chad Allen Adams, Elizabeth Lair Gerhard, Sharon Huertas Cesky, Jeffrey Milton Scherer
  • Publication number: 20090287971
    Abstract: A method and apparatus for testing a random access memory device is provided. One embodiment involves providing an interface between Logic Built in Self Test (LBIST) and Array Built in Self Test (ABIST) paths for memory testing, including providing a cross-coupled NAND device with an LBIST test path; configuring the cross-coupled NAND device for interfacing ABIST and LBIST paths by modeling a worst case scenario for timing from a domino read static random access memory (SRAM) array; and modifying data in the cross-coupled NAND device using an LBIST controlled data path at essentially the latest point in time when a read may propagate from the array to provide full AC test coverage of down stream logic.
    Type: Application
    Filed: May 15, 2008
    Publication date: November 19, 2009
    Applicant: International Business Machines Corporation
    Inventors: Chad Allen Adams, Elizabeth Lair Gerhard, Sharon Huertas Cesky, Jeffrey Milton Scherer
  • Publication number: 20080273402
    Abstract: A method and apparatus implementing domino static random access memory (SRAM) leakage current reduction include a local evaluation circuit coupled to true and complement bit lines of a pair of local SRAM cell groups, receives precharge signals and provides an output connected to a global dot line. A sleep input is applied to SRAM sleep logic and a write driver including sleep control. Data true and data complement outputs of the write driver are forced to a respective selected level to discharge the bit lines and global dot lines when the sleep input transitions high. Discharging the bit lines and global dot lines is implemented through gating in the write driver without requiring any additional devices in the local evaluation circuit.
    Type: Application
    Filed: June 23, 2008
    Publication date: November 6, 2008
    Applicant: International Business Machines Corporation
    Inventors: Todd Alan Christensen, Elizabeth Lair Gerhard, Omer Heymann, Amira Rozenfeld
  • Patent number: 7414878
    Abstract: A method and apparatus implementing domino static random access memory (SRAM) leakage current reduction include a local evaluation circuit coupled to true and complement bit lines of a pair of local SRAM cell groups, receives precharge signals and provides an output connected to a global dot line. A sleep input is applied to SRAM sleep logic and a write driver including sleep control. Data true and data complement outputs of the write driver are forced to a respective selected level to discharge the bit lines and global dot lines when the sleep input transitions high. Discharging the bit lines and global dot lines is implemented through gating in the write driver without requiring any additional devices in the local evaluation circuit.
    Type: Grant
    Filed: May 4, 2007
    Date of Patent: August 19, 2008
    Assignee: International Business Machines Corporation
    Inventors: Todd Alan Christensen, Elizabeth Lair Gerhard, Omer Heymann, Amira Rozenfeld
  • Patent number: 7206236
    Abstract: Arrays such as SRAMs, DRAMs, CAMs & Programmable ROMs having multiple independent failures are repaired using redundant bit lines. A first embodiment provides redundant bit lines on one side of the array. During a write, data is shifted towards the redundant bit lines on the one side of the array, bypassing failed bit lines. A second embodiment provides a spare bit line on each side of the array. During a write, a first failing bit line is replaced by a first spare bit line on a first side of the array, and a second failing bit line is replaced by a second spare bit line on a second side of the array.
    Type: Grant
    Filed: January 12, 2006
    Date of Patent: April 17, 2007
    Assignee: International Business Machines Corporation
    Inventors: Anthony Gus Aipperspach, Todd Alan Christensen, Elizabeth Lair Gerhard, George Francis Paulik