Patents by Inventor John Cummings Schiff

John Cummings Schiff 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: 8086977
    Abstract: A system and method for switching digital circuit clock net driver without losing clock pulses is presented. A device uses glitchless clock selection logic, which includes an edge detector, to select a clock signal to provide to device circuitry based upon the device circuitry's performance requirements. When the rising edges of a first clock signal and a second clock signal align, the edge detector momentarily pulses a clock switch signal, which is used to clock in a clock selection signal to a multiplexer. As a result, when the clock selection signal is high, the device waits until the clock edges are aligned before switching clock signals.
    Type: Grant
    Filed: August 15, 2008
    Date of Patent: December 27, 2011
    Assignee: International Business Machines Corporation
    Inventors: Jethro C. Law, Kirk Edward Morrow, John Cummings Schiff, Glen Arthur Wiedemeier
  • Patent number: 7752480
    Abstract: A system and method for switching digital circuit clock net driver without losing clock pulses is presented. A device uses glitchless clock selection logic, which includes an edge detector, to select a clock signal to provide to device circuitry based upon the device circuitry's performance requirements. When the rising edges of a first clock signal and a second clock signal align, the edge detector momentarily pulses a clock switch signal, which is used to clock in a clock selection signal to a multiplexer. As a result, when the clock selection signal is high, the device waits until the clock edges are aligned before switching clock signals.
    Type: Grant
    Filed: August 18, 2006
    Date of Patent: July 6, 2010
    Assignee: International Business Machines Corporation
    Inventors: Jethro C. Law, Kirk Edward Morrow, John Cummings Schiff, Glen Arthur Wiedemeier
  • Publication number: 20080301606
    Abstract: A system and method for switching digital circuit clock net driver without losing clock pulses is presented. A device uses glitchless clock selection logic, which includes an edge detector, to select a clock signal to provide to device circuitry based upon the device circuitry's performance requirements. When the rising edges of a first clock signal and a second clock signal align, the edge detector momentarily pulses a clock switch signal, which is used to clock in a clock selection signal to a multiplexer. As a result, when the clock selection signal is high, the device waits until the clock edges are aligned before switching clock signals.
    Type: Application
    Filed: August 15, 2008
    Publication date: December 4, 2008
    Applicant: International Business Machines Corporation
    Inventors: Jethro C. Law, Kirk Edward Morrow, John Cummings Schiff, Glen Arthur Wiedemeier
  • Publication number: 20080046776
    Abstract: A system and method for switching digital circuit clock net driver without losing clock pulses is presented. A device uses glitchless clock selection logic, which includes an edge detector, to select a clock signal to provide to device circuitry based upon the device circuitry's performance requirements. When the rising edges of a first clock signal and a second clock signal align, the edge detector momentarily pulses a clock switch signal, which is used to clock in a clock selection signal to a multiplexer. As a result, when the clock selection signal is high, the device waits until the clock edges are aligned before switching clock signals.
    Type: Application
    Filed: August 18, 2006
    Publication date: February 21, 2008
    Inventors: Jethro C. Law, Kirk Edward Morrow, John Cummings Schiff, Glen Arthur Wiedemeier
  • Patent number: 7202723
    Abstract: A signal detector circuit and digital signal receiver implementing the same. In one embodiment the digital signal receiver includes a switch point detector having a detector output and including a transistor array comprising one or more pull-up branches and one or more pull-down branches. A switch point control circuit is coupled to the switch point detector. The switch point control circuit generates branch enable signals for selectively enabling or disabling said one or more pull-up branches and said one or more pull-down branches in a detector output polarity dependent manner.
    Type: Grant
    Filed: October 7, 2004
    Date of Patent: April 10, 2007
    Assignee: International Business Machines Corporation
    Inventors: Daniel Mark Dreps, John Cummings Schiff, Glen A. Wiedemeier
  • Patent number: 6906550
    Abstract: A terminator circuit for use on a pin of an integrated circuit (IC) is disclosed. A preferred embodiment of the present invention includes a clamp circuit that turns on when the voltage at the pin exceeds a threshold value (either an upper or lower bound). Logic and biasing circuitry are used to allow multiple modes of operation by adjusting the threshold values. A particular mode may be selected at any given time so as to strike an appropriate balance between signal quality and power consumption with respect to a particular terminator or set of terminators. This prevents excessive power consumption due to terminator circuitry at inactive or infrequently active IC pins.
    Type: Grant
    Filed: June 5, 2003
    Date of Patent: June 14, 2005
    Assignee: International Business Machines Corporation
    Inventors: Daniel Mark Dreps, John Cummings Schiff
  • Publication number: 20040246021
    Abstract: A terminator circuit for use on a pin of an integrated circuit (IC) is disclosed. A preferred embodiment of the present invention includes a clamp circuit that turns on when the voltage at the pin exceeds a threshold value (either an upper or lower bound). Logic and biasing circuitry are used to allow multiple modes of operation by adjusting the threshold values. A particular mode may be selected at any given time so as to strike an appropriate balance between signal quality and power consumption with respect to a particular terminator or set of terminators. This prevents excessive power consumption due to terminator circuitry at inactive or infrequently active IC pins.
    Type: Application
    Filed: June 5, 2003
    Publication date: December 9, 2004
    Applicant: International Business Machines Corporation
    Inventors: Daniel Mark Dreps, John Cummings Schiff