Patents by Inventor Keith M. Carrig

Keith M. Carrig 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: 7454735
    Abstract: A method of designing a clock tree in an integrated circuit combines steps of making a list of all clock sinks; positioning a temporary reference insertion point (TIP); grouping the sinks together with structured clock buffers (SCBs) in a set of levels; and moving the SCBs to improve symmetry of the tree. The SCBs may be of several sizes and may be positioned horizontally or vertically and moved within limits to permit the program to calculate a complete tree.
    Type: Grant
    Filed: December 17, 2002
    Date of Patent: November 18, 2008
    Assignee: International Business Machines Corporation
    Inventors: Geetha Arthanari, Keith M. Carrig, Mark R. Lasher, Daniel R. Menard
  • Patent number: 6609228
    Abstract: A method and structure of clock optimization including creating an initial placement of clock feeding circuits according to clock signal requirements; identifying clusters of the clock feeding circuits, wherein each cluster includes a distinct clock signal supply device to which each clock feeding circuit within the cluster is connected; changing pin connections between the clock feeding circuits and clock signal supply devices to switch selected ones of the clock feeding circuits to different clusters to reduce lengths of wires between the clock feeding circuits and the clock signal supply devices within each cluster; and adjusting positions of the clock feeding circuits within design constraints to further reduce the lengths of the wires.
    Type: Grant
    Filed: November 15, 2000
    Date of Patent: August 19, 2003
    Assignee: International Business Machines Corporation
    Inventors: Paul H. Bergeron, Keith M. Carrig, Alvar A. Dean, Roger P. Gregor, David J. Hathaway, David E. Lackey, Harold E. Reindel, Larry Wissel
  • Patent number: 6204713
    Abstract: An integrated circuit chip comprises a plurality of clock distribution sub-networks each including a clock input for receiving a clock signal, each of the clock distribution sub-networks having a capacitance, as seen from the clock input, substantially equivalent to others of the clock distribution sub-networks; and a structured clock buffer having a size based on a load of the clock distribution sub-networks, and providing the clock signal to the clock distribution sub-networks.
    Type: Grant
    Filed: January 4, 1999
    Date of Patent: March 20, 2001
    Assignee: International Business Machines Corporation
    Inventors: Janice M. Adams, Keith M. Carrig, Roger P. Gregor, Daniel R. Menard
  • Patent number: 5339253
    Abstract: A signal distribution tree is constructed from the leaves to the root by pairing sinks having similar locations, latency requirements and generating function requirements, then determining the minimum cost route or routes between paired sinks, establishing at least one drive point for each minimum cost path which drive point will satisfy the latency requirements for the pair of sinks it serves and then treating each resulting set of drive points as a new sink to be paired while removing the initial sinks from the list of sinks to be paired, continuing this process iteratively until a single set of drive points results and, finally, connecting the signal source to one of the drive points in the final set.
    Type: Grant
    Filed: June 14, 1991
    Date of Patent: August 16, 1994
    Assignee: International Business Machines Corporation
    Inventors: Keith M. Carrig, David J. Hathaway, Keith W. Lallier, Jeannie T. H. Panner, Terrence W. Sehr