Patents by Inventor David A. Jefferson

David A. Jefferson 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: 6262933
    Abstract: A high-performance address decoder circuit provides higher speed read and write access for an embedded memory of a programmable logic integrated circuit. The address decoder is programmable to allow addressing of the memory in different data widths and depths. The circuitry can be used as column address decoder or row address decoder, or both. In a dual-port memory implementation of the memory, there can be two instances of each of the decoders, one for writing and one for reading.
    Type: Grant
    Filed: January 28, 2000
    Date of Patent: July 17, 2001
    Assignee: Altera Corporation
    Inventors: Wanli Chang, David Jefferson
  • Patent number: 6163195
    Abstract: A delay circuit is provided for delaying signals. The delay circuit includes: at least one inverter having a time delay; at least one current source coupled to the at least one inverter, the at least one current source providing charging current to the at least one inverter; and a voltage biasing circuit coupled to the at least one current source, the voltage biasing circuit providing a biasing voltage to the at least one current source such that the at least one current source varies the charging current so as to maintain the time delay of the at least one inverter substantially constant.
    Type: Grant
    Filed: May 26, 1999
    Date of Patent: December 19, 2000
    Assignee: Altera Corporation
    Inventor: David Jefferson
  • Patent number: 6127865
    Abstract: An integrated circuit programmable logic device comprising: a plurality of programmable logic elements that are responsive to clock signals; a clock signal generation circuit which produces a first clock signal; a first phase shifting element which produces a second clock signal which is a phase-shifted version of the first clock signal, shifted in phase by an amount which compensates for a logic signal delay; and a clock signal distribution network which distributes the first and second clock signals among the programmable logic elements.
    Type: Grant
    Filed: May 26, 1998
    Date of Patent: October 3, 2000
    Assignee: Altera Corporation
    Inventor: David Jefferson
  • Patent number: 6121790
    Abstract: A programmable logic integrated circuit device is provided with enhanced capability for dynamically multiplexing signals on the device. Controllable connectors that are provided on the device for connecting any of several connector input signals to a connector output are controlled by control signals that can be programmably selected to be either constant or variable signals. If a control signal is selected to be a variable signal, then the connector controlled by that control signal can be operated as a dynamic multiplexer of the input signals to that connector. The controllable connectors may advantageously be used as the connectors that are employed for allowing several possible signal sources to effectively share a smaller of number of signal drivers.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: September 19, 2000
    Assignee: Altera Corporation
    Inventors: Andy L. Lee, Richard G. Cliff, David Jefferson, Cameron McClintock, Kurosu R. Altaf
  • Patent number: 6094064
    Abstract: A programmable logic device architecture incorporating a peripheral overflow bus is disclosed. In a preferred embodiment, the programmable logic device has a core region that includes at least a plurality of logic cells interconnected by way of associated programmable logic cell conductors. The interconnected logic cells form an array suitable for use in implementing desired logic functions. The programmable logic device also has a peripheral region. The peripheral region includes at least a plurality of bi-directional ports of which selected ones may be coupled to external circuitry. The peripheral region also includes a bi-directional peripheral I/O overflow bus suitably arranged to pass a plurality of control signals and a plurality of data signals between the core region and the plurality of bi-directional ports.
    Type: Grant
    Filed: July 23, 1998
    Date of Patent: July 25, 2000
    Assignee: Altera Corporation
    Inventors: Manuel Mejia, David Jefferson, Srinivas Reddy
  • Patent number: 5977793
    Abstract: A programmable logic device has a plurality of super-regions of programmable logic disposed on the device in a two-dimensional array of intersecting rows and columns of super-regions. Horizontal and vertical inter-super-region interconnection conductors are associated with each row and column, respectively. Each super-region includes a plurality of regions of programmable logic, and each region includes a plurality of subregions of programmable logic. Inter-region interconnection conductors are associated with each super-region, principally for bringing signals into the super-region and interconnecting the regions in the super-region. Local conductors are associated with each region, principally for bringing signals into the region. At the super-region level the device may be horizontally and vertically isomorphic, which helps make it possible to produce devices with low aspect ratios of one or nearly one. Shared driver circuits may be provided (e.g.
    Type: Grant
    Filed: May 13, 1997
    Date of Patent: November 2, 1999
    Assignee: Altera Corporation
    Inventors: Srinivas T. Reddy, Richard G. Cliff, Christopher F. Lane, Ketan H. Zaveri, Manuel M. Mejia, David Jefferson, Bruce B. Pedersen, Andy L. Lee
  • Patent number: 5550105
    Abstract: Superconducting compositions characterized by the formula (Pb.sub.a A.sub.1-a)(Sr.sub.b Ba.sub.1-b).sub.2 (Ca.sub.c B.sub.1-c)Cu.sub.2 O.sub.7 wherein at least half the A atoms are Hg and the remainder, if any, are selected from one or more of Cd, Tl and Cu, B is selected from Y and the rare earths, a is from 0.3 to 0.7, b is from 0 to 1 and c is from 0.2 to 0.5 are disclosed. The superconductive compositions display zero-resistance temperatures up to about 80K.
    Type: Grant
    Filed: January 31, 1995
    Date of Patent: August 27, 1996
    Assignee: BICC Public Limited Comapany
    Inventors: Peter P. Edwards, Shu-Fen Hu, Ru-Shi Liu, David A. Jefferson
  • Patent number: 4520749
    Abstract: A device that contains a pocket wherein checklist cards can be inserted that match with pushbuttons that are used to indicate completion of certain steps in a series of steps.
    Type: Grant
    Filed: May 6, 1983
    Date of Patent: June 4, 1985
    Inventor: David A. Jefferson