Patents by Inventor Philip G. Shephard, III

Philip G. Shephard, III 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: 7870515
    Abstract: A method for hierarchical analysis of electronic circuits comprises selecting a first one of a plurality of abstraction levels of a general design model (GDM). The GDM comprises a first design description of electronic circuits at a plurality of abstraction levels and a plurality of foci, organized into sub-blocks. The method selects a first focus of the plurality of foci to select a first sub-block. The method identifies incomplete electronic circuits in the selected first sub-block. The method generates a second design description of the first sub-block to exclude identified incomplete electronic circuits, wherein the second design description is suitable for electronic design analysis (EDA). The method stores the generated second design description for subsequent use. Subsequent iterations thereby include all components of circuits that were incomplete in prior iterations.
    Type: Grant
    Filed: January 11, 2008
    Date of Patent: January 11, 2011
    Assignee: International Business Machines Corporation
    Inventors: Philip G. Shephard, III, Ravichander Ledalla, Vasant Rao, Jeffrey P. Soreff
  • Publication number: 20090183130
    Abstract: A method for hierarchical analysis of electronic circuits comprises selecting a first one of a plurality of abstraction levels of a general design model (GDM). The GDM comprises a first design description of electronic circuits at a plurality of abstraction levels and a plurality of foci, organized into sub-blocks. The method selects a first focus of the plurality of foci to select a first sub-block. The method identifies incomplete electronic circuits in the selected first sub-block. The method generates a second design description of the first sub-block to exclude identified incomplete electronic circuits, wherein the second design description is suitable for electronic design analysis (EDA). The method stores the generated second design description for subsequent use. Subsequent iterations thereby include all components of circuits that were incomplete in prior iterations.
    Type: Application
    Filed: January 11, 2008
    Publication date: July 16, 2009
    Inventors: Philip G. Shephard, III, Ravichander Ledalla, Vasant Rao, Jeffrey P. Soreff
  • Patent number: 7552413
    Abstract: A system and computer program for verifying performance of an array by simulating operation of edge cells in a full array model reduces the computation time required for complete design verification. The edge cells of the array (or each subarray if the array is partitioned) are subjected to a timing simulation while the center cells of the array are logically disabled, but remain in the circuit model, providing proper loading. Additional cells are specified for simulation if calculations indicate a worst-case condition due to a non-edge cell. Wordline arrivals are observed to determine worst-case rows for selection. For write operations, the difference between the wordline edges and the data edges is used to locate any non-edge “outlier” cells. For read operations, the wordline delays are summed with the bitline delays determined from edge column data to locate any outliers.
    Type: Grant
    Filed: July 2, 2008
    Date of Patent: June 23, 2009
    Assignee: International Business Machines Corporation
    Inventors: Vikas Agarwal, Michael Ju Hyeok Lee, Philip G. Shephard, III
  • Patent number: 7424691
    Abstract: A method for verifying performance of an array by simulating operation of edge cells in a full array model reduces the computation time required for complete design verification. The edge cells of the array (or each subarray if the array is partitioned) are subjected to a timing simulation while the center cells of the array are logically disabled, but remain in the circuit model, providing proper loading. Additional cells are specified for simulation if calculations indicate a worst-case condition due to a non-edge cell. Wordline arrivals are observed to determine worst-case rows for selection. For write operations, the difference between the wordline edges and the data edges is used to locate any non-edge “outlier” cells. For read operations, the wordline delays are summed with the bitline delays determined from edge column data to locate any outliers.
    Type: Grant
    Filed: April 11, 2006
    Date of Patent: September 9, 2008
    Assignee: International Business Machines Corporation
    Inventors: Vikas Agarwal, Michael Ju Hyeok Lee, Philip G. Shephard, III
  • Patent number: 7073106
    Abstract: A method, computer program product and system for testing stuck-at-faults. A first register may be loaded with a first value where the first value may be written into each entry in a memory array. A second register may be loaded with a second value. A third register may be loaded with either the second value or a third value. The second and third values are pre-selected to test selector circuits for stuck-at-faults with a pattern where the pattern includes a set of bits to be inputted to selector circuits and a set of bits to be stored in the memory cells. A value stored in the n-most significant bits in both the second and third registers may be predecoded to produce a predecode value. The predecode value may be compared with the value stored in the n-most significant bits in an entry in the memory array to determine a stuck-at-fault.
    Type: Grant
    Filed: March 19, 2003
    Date of Patent: July 4, 2006
    Assignee: International Business Machines Corporation
    Inventors: Jose A. Paredes, Philip G. Shephard, III, Timothy M. Skergan, Neil R. Vanderschaaf
  • Patent number: 5633877
    Abstract: An array built-in self test system has a scannable memory elements and a controller which, in combination, allow self test functions (e.g. test patterns, read/write access, and test sequences) to be modified without hardware changes to the test logic. Test sequence is controlled by logical test vectors, which can be changed, making the task of developing complex testing sequences relatively easy.
    Type: Grant
    Filed: May 31, 1995
    Date of Patent: May 27, 1997
    Assignee: International Business Machines Corporation
    Inventors: Philip G. Shephard, III, William V. Huott, Paul R. Turgeon, Robert W. Berry, Jr., Gulsun Yasar, Frederick J. Cox, Pradip Patel, Joseph B. Hanley, III
  • Patent number: 5375091
    Abstract: A memory embedded in a integrated processor chip is dynamically stressed tested by repeatedly writing a test pattern to the data locations of the memory in which a high percentage of the memory cells are sequentially written with complementary data in order to create a high stress on the memory devices. The test pattern is generated as a function of the number of address locations of the memory and the number of data bits of a memory data word. The test pattern is rotated each time the memory is addressed. The test pattern preferably has a contiguous group of digits with the number of digits in the contiguous group being a function of the number of address locations and the number of data bits in the memory word. The memory data input register is configured as a recirculating loop and additional dummy bits are added to provide recirculating loops longer than the data input register.
    Type: Grant
    Filed: December 8, 1993
    Date of Patent: December 20, 1994
    Assignee: International Business Machines Corporation
    Inventors: Robert W. Berry, Jr., Bernd K. F. Koenemann, William J. Scarpero, Jr., Philip G. Shephard, III, Kenneth D. Wagner, Gulsun Yasar