Patents by Inventor William P. Cornwell

William P. Cornwell 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: 7698802
    Abstract: A method for manufacturing a calibration device for an active circuit on a chip, comprises: providing an active circuit that is capable of exhibiting a desired electrical characteristic; and providing a calibration mechanism on-chip with the active circuit. The calibration mechanism generates a control output and comprises a device under test (DUT) configured as a replica of at least one segment of the active circuit, and which generates a test output that causes finite adjustments to the control output, based on a comparison of the electrical characteristics exhibited by the DUT with a known electrical characteristic. The method further comprises: attaching to each control input terminal of the active circuit a corresponding control output from the calibration mechanism. The control output of the calibration mechanism dynamically adjusts control input applied to devices of the active circuit to force the active circuit to exhibit the desired electrical characteristic.
    Type: Grant
    Filed: February 8, 2008
    Date of Patent: April 20, 2010
    Assignee: International Business Machines Corporation
    Inventors: Steven M. Clements, William P. Cornwell, Carrie E. Cox, Hayden C. Cranford, Jr., Vernon R. Norman
  • Patent number: 7570071
    Abstract: Substantially-accurate calibration of output impedance of a device-under-test (DUT) to within a predetermined range of allowable impedance. The DUT is part of a source series terminated (SST) serial link transmitter, in which two branches of parallel transistors each provide an impedance value when particular transistors of the parallel branch are turned on. The impedance value is added to a series-connected resistor to provide the output impedance. The DUT consists of one branch of parallel transistors in series with a resistor. Output impedance of the DUT is compared to the resistance of a reference resistor, and the comparator provides a control signal based on whether the output impedance falls within the pre-set percentage variance of the reference resistance. The control signal is processed by a FSM (finite state machine) that individually turns on or off the transistors within the parallel branch until the DUT impedance value falls within the desired range.
    Type: Grant
    Filed: February 8, 2008
    Date of Patent: August 4, 2009
    Assignee: International Business Machines Corporation
    Inventors: Steven M. Clements, William P. Cornwell, Carrie E. Cox, Hayden C. Cranford, Jr., Vernon R. Norman
  • Publication number: 20080122452
    Abstract: Substantially-accurate calibration of output impedance of a device-under-test (DUT) to within a predetermined range of allowable impedance. The DUT is part of a source series terminated (SST) serial link transmitter, in which two branches of parallel transistors each provide an impedance value when particular transistors of the parallel branch are turned on. The impedance value is added to a series-connected resistor to provide the output impedance. The DUT consists of one branch of parallel transistors in series with a resistor. Output impedance of the DUT is compared to the resistance of a reference resistor, and the comparator provides a control signal based on whether the output impedance falls within the pre-set percentage variance of the reference resistance. The control signal is processed by a FSM (finite state machine) that individually turns on or off the transistors within the parallel branch until the DUT impedance value falls within the desired range.
    Type: Application
    Filed: February 8, 2008
    Publication date: May 29, 2008
    Inventors: Steven M. Clements, William P. Cornwell, Carrie E. Cox, Hayden C. Cranford, Vernon R. Norman
  • Publication number: 20080120838
    Abstract: Substantially-accurate calibration of output impedance of a device-under-test (DUT) to within a predetermined range of allowable impedance. The DUT is part of a source series terminated (SST) serial link transmitter, in which two branches of parallel transistors each provide an impedance value when particular transistors of the parallel branch are turned on. The impedance value is added to a series-connected resistor to provide the output impedance. The DUT consists of one branch of parallel transistors in series with a resistor. Output impedance of the DUT is compared to the resistance of a reference resistor, and the comparator provides a control signal based on whether the output impedance falls within the pre-set percentage variance of the reference resistance. The control signal is processed by a FSM (finite state machine) that individually turns on or off the transistors within the parallel branch until the DUT impedance value falls within the desired range.
    Type: Application
    Filed: February 8, 2008
    Publication date: May 29, 2008
    Inventors: Steven M. Clements, William P. Cornwell, Carrie E. Cox, Hayden C. Cranford, Vernon R. Norman
  • Patent number: 7368902
    Abstract: Substantially-accurate calibration of output impedance of a device-under-test (DUT) to within a predetermined range of allowable impedance. The DUT is part of a source series terminated (SST) serial link transmitter, in which two branches of parallel transistors each provide an impedance value when particular transistors of the parallel branch are turned on. The impedance value is added to a series-connected resistor to provide the output impedance. The DUT consists of one branch of parallel transistors in series with a resistor. Output impedance of the DUT is compared to the resistance of a reference resistor, and the comparator provides a control signal based on whether the output impedance falls within the pre-set percentage variance of the reference resistance. The control signal is processed by a FSM (finite state machine) that individually turns on or off the transistors within the parallel branch until the DUT impedance value falls within the desired range.
    Type: Grant
    Filed: October 28, 2005
    Date of Patent: May 6, 2008
    Assignee: International Business Machines Corporation
    Inventors: Steven M. Clements, William P. Cornwell, Carrie E. Cox, Hayden C. Cranford, Jr., Vernon R. Norman
  • Patent number: 7307447
    Abstract: A circuit design method and transmitter that enables flexible control of amplitude, pre-emphasis, and slew rate utilizing a design of a segmented self-series terminated (SSST) transmitter having a parallel configuration of multiple, individually controllable segments of dual pull-up and pull-down transistors. Amplitude control, slew rate control and pre-emphasis control are enabled by manipulation/selection of normal or inverted inputs for the various segments. Also provided is a mechanism for providing/maintaining accurate output across a self-series terminated (SST) transmitter by regulating the supply voltage. Regulation of the supply voltage allows compatibility with conventional serial link receiver termination voltages and protects the transmitter output devices when those voltages are larger than the normal supply for the devices.
    Type: Grant
    Filed: October 27, 2005
    Date of Patent: December 11, 2007
    Assignee: International Business Machines Corporation
    Inventors: Steven M. Clements, William P. Cornwell, Carrie E. Cox, Hayden C. Cranford, Jr., Todd M. Rasmus