Patents by Inventor David LeRoy Guertin

David LeRoy Guertin 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: 6600347
    Abstract: A method and system for reducing a reflection coefficient below a predetermined value thereby reducing jitter by the variation of the effective impedance of a driver appearing to be bounded during state transitions. The driver may include a pull-up driver and a pull-down driver. In the pull-up driver, the transistors may be switched from a first state to a second state in a staggered fashion where the first state is complementary to the second state; In the pull-down driver, the transistors may be switched from a second state to a first state in a staggered fashion. By staggering the switching of the transistors in the pull-up driver and the pull-down driver, a portion of the current may flow from the pull-up driver to the pull-down driver thereby causing the variation of the effective impedance of the driver to appear to be bounded during state transitions.
    Type: Grant
    Filed: October 10, 2001
    Date of Patent: July 29, 2003
    Assignee: International Business Machines Corporation
    Inventors: John Michael Borkenhagen, Moises Cases, Daniel Mark Dreps, David LeRoy Guertin, Nam Huu Pham, Robert Russell Williams
  • Publication number: 20030067327
    Abstract: A method and system for reducing a reflection coefficient below a predetermined value thereby reducing jitter by the variation of the effective impedance of a driver appearing to be bounded during state transitions. The driver may comprise a pull-up driver and a pull-down driver. In the pull-driver, the transistors may be switched from a first state to a second state in a staggered fashion where the first state is complementary to the second state. In the pull-down driver, the transistors may be switched from a second state to a first state in a staggered fashion. By staggering the switching of the transistors in the pull-up driver and the pull-down driver, a portion of the current may flow from the pull-up driver to the pull-down driver thereby causing the variation of the effective impedance of the driver to appear to be bounded during state transitions.
    Type: Application
    Filed: October 10, 2001
    Publication date: April 10, 2003
    Applicant: International Business Machines Corporation
    Inventors: John Michael Borkenhagen, Moises Cases, Daniel Mark Dreps, David LeRoy Guertin, Nam Huu Pham, Robert Russell Williams
  • Patent number: 6239617
    Abstract: A mixed voltage output driver includes an output sensing circuit that senses an output voltage at an output terminal and generates a voltage signal that corresponds to a voltage level at the output terminal. Next, an impedance selection circuit receives the voltage signal and generates a control signal in response to the output voltage having a higher logical uplevel than the mixed voltage output driver. The control signal is then received by an adjustable drive impedance circuit that is also coupled to an input terminal of the mixed voltage output driver and, in response thereto, the adjustable drive impedance circuit modifies an output drive impedance of the mixed voltage output driver. In another advantageous embodiment, the mixed voltage output driver only determines if the output voltage at the output terminal is at a logical uplevel before adjusting the output drive impedance.
    Type: Grant
    Filed: November 4, 1999
    Date of Patent: May 29, 2001
    Assignee: International Business Machines Corporation
    Inventors: David LeRoy Guertin, Robert Russell Williams, Daniel Guy Young, Joseph James Cahill