Patents by Inventor Andrew D. Davies

Andrew D. Davies 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: 11750180
    Abstract: Embodiments herein describe a self-biased divider for a clock in an integrated circuit. In one embodiment, the clock includes a VCO that generates a clock signal that is output to the self-biased divider. However, because the VCO may generate an analog clocking signal (e.g., a low amplitude sine wave of unknown common mode) to reduce jitter, the amplitude can vary which means it may not sufficiently track CMOS parameters. The clocking signals generated by the self-biased divider are used as feedback signals for DC biasing (or DC leveling). In this manner, the divider is referred to a self-biased divider since signals generated by the divider are used to perform DC biasing/leveling.
    Type: Grant
    Filed: September 8, 2021
    Date of Patent: September 5, 2023
    Assignee: International Business Machines Corporation
    Inventors: James Strom, Grant P. Kesselring, Andrew D. Davies, Ann Chen Wu
  • Patent number: 11683026
    Abstract: Techniques are provided for calibrating signal currents in a radio frequency signal generator system, such as an arbitrary waveform generator system. A device comprises a current measurement circuit and a current imbalance correction circuit. The current measurement circuit is configured, during a calibration process, to measure a first current in a first signal path of a radio frequency signal generator, and to measure a second current in a second signal path of the radio frequency signal generator. The current imbalance correction circuit is configured to adjust a current level in at least one of the first signal path and the second signal path of the radio frequency signal generator to correct for an imbalance between the measured first current and the measured second current.
    Type: Grant
    Filed: August 30, 2022
    Date of Patent: June 20, 2023
    Assignee: International Business Machines Corporation
    Inventors: Sudipto Chakraborty, John Francis Bulzacchelli, Andrew D. Davies, Daniel Joseph Friedman, David James Frank
  • Publication number: 20230073824
    Abstract: Embodiments herein describe a self-biased divider for a clock in an integrated circuit. In one embodiment, the clock includes a VCO that generates a clock signal that is output to the self-biased divider. However, because the VCO may generate an analog clocking signal (e.g., a low amplitude sine wave of unknown common mode) to reduce jitter, the amplitude can vary which means it may not sufficiently track CMOS parameters. The clocking signals generated by the self-biased divider are used as feedback signals for DC biasing (or DC leveling). In this manner, the divider is referred to a self-biased divider since signals generated by the divider are used to perform DC biasing/leveling.
    Type: Application
    Filed: September 8, 2021
    Publication date: March 9, 2023
    Inventors: James STROM, Grant P. KESSELRING, Andrew D. DAVIES, Ann Chen WU
  • Patent number: 11539347
    Abstract: A radio frequency (RF) transmission circuit includes an input stage, a current-mode mixer coupled to an output of the input stage, an attenuator coupled to an output of the current-mode mixer, and a matching network coupled to an output of the attenuator. The input stage, current-mode mixer, attenuator, and the matching network are configured in a series stack.
    Type: Grant
    Filed: September 3, 2021
    Date of Patent: December 27, 2022
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Sudipto Chakraborty, John Francis Bulzacchelli, David James Frank, Andrew D. Davies
  • Patent number: 11496094
    Abstract: A voltage-controlled oscillator comprises a varactor. A capacitance of the first varactor is dependent upon a control voltage. The voltage-controlled also comprises an inductor. The inductor is connected to a center-tap connection. The voltage-controlled oscillator also comprises a power source. The power source is configured to provide a bias voltage to the inductor through the center-tap connection. The voltage-controlled oscillator also comprises a coupling capacitor. The coupling capacitor is located between the inductor and the varactor. The voltage-controlled oscillator also comprises a coupling resistor. The coupling resistor is located between the coupling capacitor and the center-tap connection. The center-tap connection provides the bias voltage to the coupling capacitor through the coupling resistor.
    Type: Grant
    Filed: April 26, 2021
    Date of Patent: November 8, 2022
    Assignee: International Business Machines Corporation
    Inventors: James Strom, Herschel Akiba Ainspan, Andrew D. Davies, John Borkenhagen
  • Publication number: 20220345085
    Abstract: A voltage-controlled oscillator comprises a varactor. A capacitance of the first varactor is dependent upon a control voltage. The voltage-controlled also comprises an inductor. The inductor is connected to a center-tap connection. The voltage-controlled oscillator also comprises a power source. The power source is configured to provide a bias voltage to the inductor through the center-tap connection. The voltage-controlled oscillator also comprises a coupling capacitor. The coupling capacitor is located between the inductor and the varactor. The voltage-controlled oscillator also comprises a coupling resistor. The coupling resistor is located between the coupling capacitor and the center-tap connection. The center-tap connection provides the bias voltage to the coupling capacitor through the coupling resistor.
    Type: Application
    Filed: April 26, 2021
    Publication date: October 27, 2022
    Inventors: James Strom, Herschel Akiba Ainspan, Andrew D. Davies, John Borkenhagen
  • Patent number: 10326450
    Abstract: A method and circuit for implementing a level shifter for translating logic signals to output voltage analog levels, and a design structure on which the subject circuit resides are provided. The circuit includes a level shifter resistor divider string of a plurality of series connected resistors, the level shifter resistor divider string is connected between an analog voltage rail and an analog ground. A plurality of level shifter cascaded inverters are connected between respective resistors of the level shifter resistor divider string and an analog voltage rail and an analog ground. An output of the level shifter is programmed by the level shifter resistor divider string connected to the cascaded inverters.
    Type: Grant
    Filed: June 8, 2017
    Date of Patent: June 18, 2019
    Assignee: International Business Machines Corporation
    Inventors: Andrew D. Davies, David M. Friend, Grant P. Kesselring, James D. Strom
  • Publication number: 20180358969
    Abstract: A method and circuit for implementing a level shifter for translating logic signals to output voltage analog levels, and a design structure on which the subject circuit resides are provided. The circuit includes a level shifter resistor divider string of a plurality of series connected resistors, the level shifter resistor divider string is connected between an analog voltage rail and an analog ground. A plurality of level shifter cascaded inverters are connected between respective resistors of the level shifter resistor divider string and an analog voltage rail and an analog ground. An output of the level shifter is programmed by the level shifter resistor divider string connected to the cascaded inverters.
    Type: Application
    Filed: June 8, 2017
    Publication date: December 13, 2018
    Inventors: Andrew D. Davies, David M. Friend, Grant P. Kesselring, James D. Strom
  • Patent number: 10116260
    Abstract: A system includes a voltage controlled oscillator (VCO) having an adjustable amplitude. The amplitude of the VCO may be adjusted by adjusting voltage level present at a center tap node of an inductor. The VCO may have an adjustable amplitude that may be programmed on a chip-by-chip basis based on a chip parameter, power consumption, or oscillator performance.
    Type: Grant
    Filed: December 16, 2015
    Date of Patent: October 30, 2018
    Assignee: International Business Machines Corporation
    Inventors: Andrew D. Davies, David M. Friend, Christopher W. Steffen, James D. Strom
  • Publication number: 20170179884
    Abstract: A system includes a voltage controlled oscillator (VCO) having an adjustable amplitude. The amplitude of the VCO may be adjusted by adjusting voltage level present at a center tap node of an inductor. The VCO may have an adjustable amplitude that may be programmed on a chip-by-chip basis based on a chip parameter, power consumption, or oscillator performance.
    Type: Application
    Filed: December 16, 2015
    Publication date: June 22, 2017
    Inventors: Andrew D. Davies, David M. Friend, Christopher W. Steffen, James D. Strom
  • Patent number: 9571069
    Abstract: A method and a clock receiver circuit for implementing low jitter and enhanced duty cycle, and a design structure on which the subject circuit resides are provided. The clock receiver circuit accepts single-ended complementary metal oxide semiconductor (CMOS) and differential clock signals. The clock receiver circuit includes input circuitry coupled to a differential pair that biasing a reference clock and allows for single-ended or differential clock signals. The differential pair uses multiple current mirrors for switching the polarity of the input signals to achieve enhanced jitter performance, and cross coupled inverters for retaining signal symmetry.
    Type: Grant
    Filed: April 25, 2015
    Date of Patent: February 14, 2017
    Assignee: International Business Machines Corporation
    Inventors: Andrew D. Davies, Grant P. Kesselring, Christopher W. Steffen, James D. Strom
  • Patent number: 9438209
    Abstract: A method and a clock receiver circuit for implementing low jitter and enhanced duty cycle, and a design structure on which the subject circuit resides are provided. The clock receiver circuit accepts single-ended complementary metal oxide semiconductor (CMOS) and differential clock signals. The clock receiver circuit includes input circuitry coupled to a differential pair that biasing a reference clock and allows for single-ended or differential clock signals. The differential pair uses multiple current mirrors for switching the polarity of the input signals to achieve enhanced jitter performance, and cross coupled inverters for retaining signal symmetry.
    Type: Grant
    Filed: December 29, 2014
    Date of Patent: September 6, 2016
    Assignee: International Business Machines Corporation
    Inventors: Andrew D. Davies, Grant P. Kesselring, Christopher W. Steffen, James D. Strom
  • Publication number: 20160191024
    Abstract: A method and a clock receiver circuit for implementing low jitter and enhanced duty cycle, and a design structure on which the subject circuit resides are provided. The clock receiver circuit accepts single-ended complementary metal oxide semiconductor (CMOS) and differential clock signals. The clock receiver circuit includes input circuitry coupled to a differential pair that biasing a reference clock and allows for single-ended or differential clock signals. The differential pair uses multiple current mirrors for switching the polarity of the input signals to achieve enhanced jitter performance, and cross coupled inverters for retaining signal symmetry.
    Type: Application
    Filed: April 25, 2015
    Publication date: June 30, 2016
    Inventors: Andrew D. Davies, Grant P. Kesselring, Christopher W. Steffen, James D. Strom
  • Publication number: 20160191023
    Abstract: A method and a clock receiver circuit for implementing low jitter and enhanced duty cycle, and a design structure on which the subject circuit resides are provided. The clock receiver circuit accepts single-ended complementary metal oxide semiconductor (CMOS) and differential clock signals. The clock receiver circuit includes input circuitry coupled to a differential pair that biasing a reference clock and allows for single-ended or differential clock signals. The differential pair uses multiple current minors for switching the polarity of the input signals to achieve enhanced jitter performance, and cross coupled inverters for retaining signal symmetry.
    Type: Application
    Filed: December 29, 2014
    Publication date: June 30, 2016
    Inventors: Andrew D. Davies, Grant P. Kesselring, Christopher W. Steffen, James D. Strom
  • Publication number: 20150171790
    Abstract: A variable frequency oscillator device includes a first inverter stage that is designed to invert an input signal to generate a sawtooth signal by charging and discharging a capacitor using current sources that each provides a respective amount of current that is responsive to a control signal and to a dampening signal. A second inverter stage is designed to generate a first inverted signal from the sawtooth signal of the first inverter stage. A third inverter stage is designed to generate a second inverted signal from the first inverted signal, and dampen a signal transition rate for the first inverted signal based upon the control signal.
    Type: Application
    Filed: December 17, 2013
    Publication date: June 18, 2015
    Applicant: International Business Machines Corporation
    Inventors: Andrew D. Davies, Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom
  • Patent number: 9059660
    Abstract: A variable frequency oscillator device includes a first inverter stage that is designed to invert an input signal to generate a sawtooth signal by charging and discharging a capacitor using current sources that each provides a respective amount of current that is responsive to a control signal and to a dampening signal. A second inverter stage is designed to generate a first inverted signal from the sawtooth signal of the first inverter stage. A third inverter stage is designed to generate a second inverted signal from the first inverted signal, and dampen a signal transition rate for the first inverted signal based upon the control signal.
    Type: Grant
    Filed: December 17, 2013
    Date of Patent: June 16, 2015
    Assignee: International Business Machines Corporation
    Inventors: Andrew D. Davies, Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom
  • Patent number: 7940878
    Abstract: A phase locked loop generates an output corresponding to a source synchronous input and an input link clock signal. A phase locking feedback system receives the input and an input link clock signal and detects phase deviations between the output and the input. The phase locking feedback system also adjusts an adjusted clock signal based on the phase deviations thereby causing the phase locking feedback system to generate the output so that the output has a steady phase relationship with the input. A first mechanism causes the phase locking feedback system not to track phase deviations between the output and the input upon occurrence of a first predefined event, thereby maintaining the adjusted clock signal at a current state.
    Type: Grant
    Filed: February 23, 2007
    Date of Patent: May 10, 2011
    Assignee: International Business Machines Corporation
    Inventors: Steven J. Baumgartner, Timothy C. Buchholtz, Andrew D. Davies, Thomas W. Liang, Andrew B. Maki, Thomas Pham, Dana M. Woeste, Daniel G. Young
  • Publication number: 20080205570
    Abstract: A phase locked loop generates an output corresponding to a source synchronous input and an input link clock signal. A phase locking feedback system receives the input and an input link clock signal and detects phase deviations between the output and the input. The phase locking feedback system also adjusts an adjusted clock signal based on the phase deviations thereby causing the phase locking feedback system to generate the output so that the output has a steady phase relationship with the input. A first mechanism causes the phase locking feedback system not to track phase deviations between the output and the input upon occurrence of a first predefined event, thereby maintaining the adjusted clock signal at a current state.
    Type: Application
    Filed: February 23, 2007
    Publication date: August 28, 2008
    Inventors: Steven J. Baumgartner, Timothy C. Buchholtz, Andrew D. Davies, Thomas W. Liang, Andrew B. Maki, Thomas Pham, Dana M. Woeste, Daniel G. Young