Patents by Inventor April M. Graham

April M. Graham 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: 9419636
    Abstract: In one example, a current steering circuit includes an output transistor pair responsive to a first gate bias voltage. The current steering circuit further includes a first switch comprising a first source-coupled transistor pair coupled to the output transistor pair and responsive to a first differential gate voltage, and a second switch comprising a second source-coupled transistor pair coupled to the output transistor pair and responsive to a second differential gate voltage. The current steering circuit further includes a current source configured to source a bias current. The current steering circuit further includes a third switch comprising a third source-coupled transistor pair coupled between the current source and each of the first switch and the second switch, the third source-coupled transistor pair responsive to a third differential gate voltage.
    Type: Grant
    Filed: April 9, 2015
    Date of Patent: August 16, 2016
    Assignee: XILINX, INC.
    Inventors: April M. Graham, Edward Cullen, Conrado K. Mesadri
  • Patent number: 8922412
    Abstract: An apparatus relating generally to digital-to-analog conversion is disclosed. In such an apparatus, a digital-to-analog converter (“DAC”) device includes a source DAC and a sink DAC selectively coupled to one another. The source DAC provides a first bias to the sink DAC in a sink mode, and the sink DAC provides a second bias to the source DAC in a source mode.
    Type: Grant
    Filed: April 30, 2013
    Date of Patent: December 30, 2014
    Assignee: Xilinx, Inc.
    Inventors: Christopher M. Gorman, April M. Graham, John K. Jennings
  • Patent number: 8836409
    Abstract: An apparatus includes: a switch having a first transistor, the first transistor having a gate, wherein the switch is connected between a first pad and a second pad; and a first biasing circuit coupled to the gate of the first transistor, wherein the first biasing circuit is configured for outputting a first voltage, the first voltage being the lowest one of (1) a voltage of the first pad, (2) a voltage of the second pad, and (3) a ground voltage; wherein the gate of the first transistor is driven by the first voltage from the first biasing circuit in response to an enable signal being set for configuring the switch to be off.
    Type: Grant
    Filed: March 11, 2013
    Date of Patent: September 16, 2014
    Assignee: Xilinx, Inc.
    Inventors: Edward Cullen, April M. Graham, Ionut C. Cical