Patents by Inventor David M. Friend

David M. Friend 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: 9455730
    Abstract: A feedback module for preventing voltage controlled oscillator (VCO) runaway in a phase locked loop (PLL) circuit can include a first, a second, and a third input to receive a first output signal from a PLL circuit, a reference signal, and a first control signal. The feedback module may also include a feedback circuit to generate a second control signal, the second control signal being coupled to an input of the PLL circuit, wherein the feedback circuit generates the second control signal by comparing a number of cycles of the first output signal to a first threshold, and a number of cycles of the reference signal to a second threshold.
    Type: Grant
    Filed: June 9, 2015
    Date of Patent: September 27, 2016
    Assignee: International Business Machines Corporation
    Inventors: David M. Friend, James D. Strom, Alan P. Wagstaff
  • Patent number: 9391623
    Abstract: A feedback module for preventing voltage controlled oscillator (VCO) runaway in a phase locked loop (PLL) circuit can include a first, a second, and a third input to receive a first output signal from a PLL circuit, a reference signal, and a first control signal. The feedback module may also include a feedback circuit to generate a second control signal, the second control signal being coupled to an input of the PLL circuit, wherein the feedback circuit generates the second control signal by comparing a number of cycles of the first output signal to a first threshold, and a number of cycles of the reference signal to a second threshold.
    Type: Grant
    Filed: January 11, 2016
    Date of Patent: July 12, 2016
    Assignee: International Business Machines Corporation
    Inventors: David M. Friend, James D. Strom, Alan P. Wagstaff
  • Publication number: 20160142062
    Abstract: A phase-frequency detector (PFD) is electrically coupled to a charge pump of a phase-locked-loop (PLL). The PFD includes a first differential latch electrically coupled to the charge pump. The first differential latch drives a differential pair of increment signals to the charge pump in response to differential pairs of both reference clock signals and reset signals. The PFD also includes a second differential latch electrically coupled to the charge pump. The second differential latch drives a differential pair of decrement signals to the charge pump in response to differential pairs of both feedback clock signals and reset signals. The PFD also includes a differential AND gate electrically coupled to both the first differential latch and the second differential latch. The differential AND gate drives the differential pair of reset signals to both of the differential latches in response to the differential pairs of both increment signals and decrement signals.
    Type: Application
    Filed: November 19, 2014
    Publication date: May 19, 2016
    Inventors: David M. Friend, Grant P. Kesselring, James D. Strom, Alan P. Wagstaff
  • Patent number: 9197225
    Abstract: A circuit for implementing a control voltage mirror is provided. A filter includes a filter capacitor connected to a control voltage and a distal side of the capacitor connected to a voltage reference. The control voltage mirror includes an operational amplifier having a positive input connected to the control voltage, and a negative input is connected to an output and coupled to the distal side of the capacitor. Voltage across the capacitor is held to be near or at zero volts, substantially eliminating capacitor leakage current.
    Type: Grant
    Filed: October 5, 2011
    Date of Patent: November 24, 2015
    Assignee: International Business Machines Corporation
    Inventors: Kennedy K. Cheruiyot, Joel T. Ficke, David M. Friend, Grant P. Kesselring, 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: 8994117
    Abstract: A semiconductor chip having a P? substrate and an N+ epitaxial layer grown on the P? substrate is shown. A P? circuit layer is grown on top of the N+ epitaxial layer. A first moat having an electrically quiet ground connected to a first N+ epitaxial region is created by isolating the first N+ epitaxial region with a first deep trench. The first moat is surrounded, except for a DC path, by a second moat with a second N+ epitaxial region, created by isolating the second N+ epitaxial region with a second deep trench. The second moat may be arranged as a rectangular spiral around the first moat.
    Type: Grant
    Filed: December 18, 2012
    Date of Patent: March 31, 2015
    Assignee: International Business Machines Corporation
    Inventors: Joel T. Ficke, David M. Friend, James D. Strom, Erik S. Unterborn
  • Patent number: 8917126
    Abstract: A system is disclosed, which may include a differential charge pump. The differential charge pump may include a first and a second H-bridge circuit, each driving, on a respective output, an output current that is substantially similar over an output voltage operating range. The differential charge pump may be designed to receive increment, decrement and bias signals, and drive, in response to the increment and decrement signals, the output current to draw each H-bridge circuit output towards a first or a second supply voltage. The differential charge pump may also be designed to increase, in response to the bias signals, the output voltage operating range over which the output current is substantially similar. The differential charge pump may also include a bias signal generator, designed to generate bias signals in response to H-bridge circuit output voltages.
    Type: Grant
    Filed: December 23, 2013
    Date of Patent: December 23, 2014
    Assignee: International Business Machines Corporation
    Inventors: Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom
  • Patent number: 8751982
    Abstract: A method and circuit for implementing a dual speed level shifter with automatic mode control, and a design structure on which the subject circuit resides are provided. A low speed level shifter and a high speed level shifter are used to provide a wide frequency range of operation. The circuit operates in one of a low speed mode or a high speed mode. The appropriate mode is selected automatically by detecting the frequency of the signal to be level shifted. When the incoming signal is slower than a reference frequency, the low speed level shifter is selected, and when the incoming signal is faster than the reference frequency, the high speed level shifter is selected.
    Type: Grant
    Filed: September 2, 2012
    Date of Patent: June 10, 2014
    Assignee: International Business Machines Corporation
    Inventors: Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom, Jianguo Yao
  • Patent number: 8513957
    Abstract: A method and circuit for implementing dynamic voltage sensing and a trigger circuit, and a design structure on which the subject circuits resides are provided. The voltage sensing circuit includes a first quiet oscillator generating a reference clock, and a second noisy oscillator generating a noisy clock. A digital control loop coupled to the first quiet oscillator and the second noisy oscillator matches frequency of the first quiet oscillator and the second noisy oscillator. The reference clock drives a first predefined-bit shift register and the noisy clock drives a second predefined-bit shift register, where the second predefined-bit shift register is greater than the first predefined-bit shift register. When the first predefined-bit shift register overflows, the contents of the second predefined-bit shift register are evaluated. The contents of the second predefined-bit shift register are compared with a noise threshold select value to identify a noise event and trigger a noise detector control output.
    Type: Grant
    Filed: June 2, 2010
    Date of Patent: August 20, 2013
    Assignee: International Business Machines Corporation
    Inventors: Kennedy K. Cheruiyot, Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom
  • Publication number: 20130088269
    Abstract: A circuit for implementing a control voltage mirror for phase error and jitter performance optimization and a design structure on which the subject circuit resides are provided. The control voltage mirror is used with a phase locked loop filter utilizing a thin oxide filter capacitor connected to a control voltage and a distal side of the capacitor connected to a voltage reference. The control voltage mirror includes an operational amplifier holding voltage across the capacitor to be near or at zero volts, substantially eliminating capacitor leakage current to provide phase error and jitter performance optimization.
    Type: Application
    Filed: October 5, 2011
    Publication date: April 11, 2013
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kennedy K. Cheruiyot, Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom
  • Publication number: 20120331432
    Abstract: A method and circuit for implementing a dual speed level shifter with automatic mode control, and a design structure on which the subject circuit resides are provided. A low speed level shifter and a high speed level shifter are used to provide a wide frequency range of operation. The circuit operates in one of a low speed mode or a high speed mode. The appropriate mode is selected automatically by detecting the frequency of the signal to be level shifted. When the incoming signal is slower than a reference frequency, the low speed level shifter is selected, and when the incoming signal is faster than the reference frequency, the high speed level shifter is selected.
    Type: Application
    Filed: September 2, 2012
    Publication date: December 27, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom, Jianguo Yao
  • Patent number: 8324933
    Abstract: A method and circuit for implementing a dual speed level shifter with automatic mode control, and a design structure on which the subject circuit resides are provided. A low speed level shifter and a high speed level shifter are used to provide a wide frequency range of operation. The circuit operates in one of a low speed mode or a high speed mode. The appropriate mode is selected automatically by detecting the frequency of the signal to be level shifted. When the incoming signal is slower than a reference frequency, the low speed level shifter is selected, and when the incoming signal is faster than the reference frequency, the high speed level shifter is selected.
    Type: Grant
    Filed: February 18, 2011
    Date of Patent: December 4, 2012
    Assignee: International Business Machines Corporation
    Inventors: Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom, Jianguo Yao
  • Publication number: 20120212280
    Abstract: A method and circuit for implementing a dual speed level shifter with automatic mode control, and a design structure on which the subject circuit resides are provided. A low speed level shifter and a high speed level shifter are used to provide a wide frequency range of operation. The circuit operates in one of a low speed mode or a high speed mode. The appropriate mode is selected automatically by detecting the frequency of the signal to be level shifted. When the incoming signal is slower than a reference frequency, the low speed level shifter is selected, and when the incoming signal is faster than the reference frequency, the high speed level shifter is selected.
    Type: Application
    Filed: February 18, 2011
    Publication date: August 23, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom, Jianguo Yao
  • Publication number: 20110298474
    Abstract: A method and circuit for implementing dynamic voltage sensing and a trigger circuit, and a design structure on which the subject circuits resides are provided. The voltage sensing circuit includes a first quiet oscillator generating a reference clock, and a second noisy oscillator generating a noisy clock. A digital control loop coupled to the first quiet oscillator and the second noisy oscillator matches frequency of the first quiet oscillator and the second noisy oscillator. The reference clock drives a first predefined-bit shift register and the noisy clock drives a second predefined-bit shift register, where the second predefined-bit shift register is greater than the first predefined-bit shift register. When the first predefined-bit shift register overflows, the contents of the second predefined-bit shift register are evaluated. The contents of the second predefined-bit shift register are compared with a noise threshold select value to identify a noise event and trigger a noise detector control output.
    Type: Application
    Filed: June 2, 2010
    Publication date: December 8, 2011
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kennedy K. Cheruiyot, Joel T. Ficke, David M. Friend, Grant P. Kesselring, James D. Strom
  • Publication number: 20100001804
    Abstract: A system to improve a voltage-controlled oscillator may include a voltage-controlled oscillator. The system may also include a switch to control a first voltage passing through the voltage-controlled oscillator based upon a digital tune bit used to control the voltage-controlled oscillator's gain.
    Type: Application
    Filed: July 6, 2008
    Publication date: January 7, 2010
    Inventors: David M. Friend, George E. Smith, III, Michael Sperling, James D. Strom
  • Publication number: 20090189653
    Abstract: A method and apparatus and program use the quiet, regulated power supply inherent to the PLL to drive a CMOS buffer. In this manner, the CMOS buffer may distribute the reference clock in a manner that minimizes the power and space consumption associated with clock distribution processes.
    Type: Application
    Filed: January 28, 2008
    Publication date: July 30, 2009
    Inventors: David M. Friend, James D. Strom
  • Patent number: 6437602
    Abstract: A fully dynamic logic network and method of operation thereof. The dynamic logic network includes a number of dynamic switching circuits, where each of dynamic switching circuits generates an output signal. In an advantageous embodiment, each of the dynamic switching circuits is a dynamic domino gate. The dynamic logic network also includes a dynamic logic circuit that is coupled to the dynamic switching circuits. The dynamic logic circuit, in turn, includes a clock generation circuit and a logic switching circuit that in a preferred embodiment is a dynamic NOR, or alternatively, NAND gate. The clock generation circuit receives the output signals from the dynamic switching circuits and generates, in response thereto, a control signal. The logic switching circuit also receives the output signals from the dynamic switching circuits and generates a logic output signal in response to a state of the control signal generated by the clock generation circuit.
    Type: Grant
    Filed: July 12, 2001
    Date of Patent: August 20, 2002
    Assignee: International Business Machines Corporation
    Inventors: David M. Friend, Nghia Van Phan