Patents by Inventor Roxanne T. Vu

Roxanne T. Vu 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: 7199605
    Abstract: An apparatus is described having a feedback loop. The feedback loop has an output that approaches a steady state as a data line voltage approaches a reference voltage. The apparatus also includes a driving transistor that drives the data line. The driving transistor has an output impedance that is controlled by the feedback loop output, the feedback loop output keeps the driving transistor output impedance within a high output impedance region when the feedback loop output reaches the steady state.
    Type: Grant
    Filed: June 1, 2005
    Date of Patent: April 3, 2007
    Assignee: Rambus Inc.
    Inventors: Leung Yu, Roxanne T. Vu, Benedict C. Lau, Huy M. Nguyen, James A. Gasbarro
  • Patent number: 7135903
    Abstract: A phase-jumping locked loop circuit. The locked loop circuit includes a plurality of differential amplifiers and a biasing circuit switchably coupled to each of the differential amplifiers. Each of the differential amplifiers has inputs to receive a respective pair of clock signals and outputs coupled to a common pair of output signal lines. The biasing circuit comprising a first plurality of biasing transistors coupled in parallel with one another and in series with a first set of the differential amplifiers, and a second plurality of biasing transistors coupled in parallel with one another and in series with a second set of the differential amplifiers.
    Type: Grant
    Filed: February 25, 2003
    Date of Patent: November 14, 2006
    Assignee: Rambus Inc.
    Inventors: Jade M. Kizer, Benedict C. Lau, Roxanne T. Vu, Huy M. Nguyen, Leung Yu, Adam Chuen-Huei Chou
  • Patent number: 7046078
    Abstract: An integrated circuit has one or more components that operate with reference to a distributed reference voltage. A reference voltage driver produces a compensated reference voltage, and the compensated reference voltage is distributed to form the distributed reference voltage at the components. Due to factors such as trace resistance and gate leakage, the distributed reference voltage is degraded relative to the compensated reference voltage. The reference voltage driver is responsive to feedback derived from the distributed reference voltage to adjust the compensated reference voltage so that the distributed reference voltage is approximately equal to a nominal reference voltage.
    Type: Grant
    Filed: May 11, 2005
    Date of Patent: May 16, 2006
    Assignee: Rambus Inc.
    Inventors: Huy M. Nguyen, Benedict C. Lau, Adam Chuen-Huei Chou, Roxanne T. Vu
  • Patent number: 7038543
    Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: May 2, 2006
    Assignee: Rambus Inc.
    Inventors: Huey M. Nguyen, Benedict C. Lau, Leung Yu, Jade M. Kizer, Roxanne T. Vu
  • Patent number: 7002367
    Abstract: An apparatus is described having a feedback loop. The feedback loop has an output that approaches a steady state as a data line voltage approaches a reference voltage. The apparatus also includes a driving transistor that drives the data line. The driving transistor has an output impedance that is controlled by the feedback loop output, the feedback loop output keeps the driving transistor output impedance within a high output impedance region when the feedback loop output reaches the steady state.
    Type: Grant
    Filed: January 21, 2003
    Date of Patent: February 21, 2006
    Assignee: Rambus, Inc.
    Inventors: Leung Yu, Roxanne T. Vu, Benedict C. Lau, Huy M. Nguyen, James A. Gasbarro
  • Patent number: 6967514
    Abstract: Adjusting a clock duty cycle. An incremental error signal is generated in response to the clock signal. A cumulative error signal is generated in response to the incremental error signal. The incremental error signal is reset and the duty cycle of the clock signal is adjusted in response to the cumulative error signal.
    Type: Grant
    Filed: October 21, 2002
    Date of Patent: November 22, 2005
    Assignee: Rambus, Inc.
    Inventors: Jade M. Kizer, Roxanne T. Vu
  • Patent number: 6960948
    Abstract: An integrated circuit device having a select circuit, a summing circuit and a phase mixer. The select circuit selects one of a plurality of offset values as a selected offset. The summing circuit sums the selected offset with a phase count value, the phase count value indicating a phase difference between a reference clock signal and a first plurality of clock signals. The phase mixer combines the first plurality of clock signals in accordance with the sum of the selected offset and the phase count value to generate an output clock signal.
    Type: Grant
    Filed: May 24, 2004
    Date of Patent: November 1, 2005
    Assignee: Rambus Inc.
    Inventors: Jade M. Kizer, Benedict C. Lau, Roxanne T. Vu, Craig E. Hampel
  • Patent number: 6897713
    Abstract: An integrated circuit has one or more components that operate with reference to a distributed reference voltage. A reference voltage driver produces a compensated reference voltage, and the compensated reference voltage is distributed to form the distributed reference voltage at the components. Due to factors such as trace resistance and gate leakage, the distributed reference voltage is degraded relative to the compensated reference voltage. The reference voltage driver is responsive to feedback derived from the distributed reference voltage to adjust the compensated reference voltage so that the distributed reference voltage is approximately equal to a nominal reference voltage.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: May 24, 2005
    Assignee: Rambus Inc.
    Inventors: Huy M. Nguyen, Benedict C. Lau, Adam Chuen-Huei Chou, Roxanne T. Vu
  • Publication number: 20040189393
    Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.
    Type: Application
    Filed: April 2, 2004
    Publication date: September 30, 2004
    Inventors: Huey M. Nguyen, Benedict C. Lau, Leung Yu, Jade M. Kizer, Roxanne T. Vu
  • Patent number: 6759881
    Abstract: An integrated circuit device having a select circuit, a summing circuit and a phase mixer. The select circuit selects one of a plurality of offset values as a selected offset. The summing circuit sums the selected offset with a phase count value, the phase count value indicating a phase difference between a reference clock signal and a first plurality of clock signals. The phase mixer combines the first plurality of clock signals in accordance with the sum of the selected offset and the phase count value to generate an output clock signal.
    Type: Grant
    Filed: February 25, 2003
    Date of Patent: July 6, 2004
    Assignee: Rambus Inc.
    Inventors: Jade M. Kizer, Benedict C. Lau, Roxanne T. Vu, Craig E. Hampel
  • Patent number: 6727759
    Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.
    Type: Grant
    Filed: May 23, 2003
    Date of Patent: April 27, 2004
    Assignee: Rambus Inc.
    Inventors: Huey M. Nguyen, Benedict C. Lau, Leung Yu, Jade M. Kizer, Roxanne T. Vu
  • Publication number: 20040041604
    Abstract: A phase-jumping locked loop circuit. The locked loop circuit includes a plurality of differential amplifiers and a biasing circuit switchably coupled to each of the differential amplifiers. Each of the differential amplifiers has inputs to receive a respective pair of clock signals and outputs coupled to a common pair of output signal lines. The biasing circuit comprising a first plurality of biasing transistors coupled in parallel with one another and in series with a first set of the differential amplifiers, and a second plurality of biasing transistors coupled in parallel with one another and in series with a second set of the differential amplifiers.
    Type: Application
    Filed: February 25, 2003
    Publication date: March 4, 2004
    Inventors: Jade M. Kizer, Benedict C. Lau, Roxanne T. Vu, Huy M. Nguyen, Leung Yu, Adam Chuen-Huei Chou
  • Publication number: 20030218504
    Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.
    Type: Application
    Filed: May 23, 2003
    Publication date: November 27, 2003
    Inventors: Huey M. Nguyen, Benedict C. Lau, Leung Yu, Jade M. Kizer, Roxanne T. Vu
  • Publication number: 20030183842
    Abstract: An integrated circuit device having a select circuit, a summing circuit and a phase mixer. The select circuit selects one of a plurality of offset values as a selected offset. The summing circuit sums the selected offset with a phase count value, the phase count value indicating a phase difference between a reference clock signal and a first plurality of clock signals. The phase mixer combines the first plurality of clock signals in accordance with the sum of the selected offset and the phase count value to generate an output clock signal.
    Type: Application
    Filed: February 25, 2003
    Publication date: October 2, 2003
    Inventors: Jade M. Kizer, Benedict C. Lau, Roxanne T. Vu, Craig E. Hampel
  • Publication number: 20030141896
    Abstract: An apparatus is described having a feedback loop. The feedback loop has an output that approaches a steady state as a data line voltage approaches a reference voltage. The apparatus also includes a driving transistor that drives the data line. The driving transistor has an output impedance that is controlled by the feedback loop output, the feedback loop output keeps the driving transistor output impedance within a high output impedance region when the feedback loop output reaches the steady state.
    Type: Application
    Filed: January 21, 2003
    Publication date: July 31, 2003
    Inventors: Leung Yu, Roxanne T. Vu, Benedict C. Lau, Huy M. Nguyen, James A. Gasbarro
  • Patent number: 6600374
    Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.
    Type: Grant
    Filed: June 25, 2001
    Date of Patent: July 29, 2003
    Assignee: Rambus Inc.
    Inventors: Huey M. Nguyen, Benedict C. Lau, Leung Yu, Jade M. Kizer, Roxanne T. Vu
  • Patent number: 6509756
    Abstract: An apparatus is described having a feedback loop. The feedback loop-has an output that approaches a steady state as a data line voltage approaches a reference voltage. The apparatus also includes a driving transistor that drives the data line. The driving transistor has an output impedance that is controlled by the feedback loop output, the feedback loop output keeps the driving transistor output impedance within a high output impedance region when the feedback loop output reaches the steady state.
    Type: Grant
    Filed: March 29, 2001
    Date of Patent: January 21, 2003
    Assignee: Rambus Inc.
    Inventors: Leung Yu, Roxanne T. Vu, Benedict C. Lau, Huy M. Nguyen, James A. Gasbarro
  • Publication number: 20020196081
    Abstract: A data receiver includes group envelope detection circuitry that produces a group envelope voltage. The group envelope voltage represents the average envelope of a plurality of amplified data signals. Associated feedback adjusts the gains applied to each data signal to minimize any difference between the group envelope voltage and a reference voltage. The reference voltage is preferably the envelope of a clock signal associated with the data signals.
    Type: Application
    Filed: June 25, 2001
    Publication date: December 26, 2002
    Inventors: Huey M. Nguyen, Benedict C. Lau, Leung Yu, Jade M. Kizer, Roxanne T. Vu
  • Patent number: 6369652
    Abstract: A differential amplifier has unequal resistance in its legs that compensates for an unequal current flow through the legs during a logic zero data input compared to logic one data input. The unequal resistance may be provided by adding a resistor in parallel to the leg that carries greater current during amplification, lowering the resistance in that leg and also the voltage that is output from that leg. Alternatively, a variable resistance may be provided to at least one of the legs to compensate for current inequalities between the legs. The variable resistance may be provided by a transistor that is controlled by a signal indicating process, voltage and/or temperature conditions of the amplifier and adjacent circuitry. Transistors may be employed in both legs as well as in a current source for the amplifier, providing balanced current regulation for the amplifier.
    Type: Grant
    Filed: May 15, 2000
    Date of Patent: April 9, 2002
    Assignee: Rambus Inc.
    Inventors: Huy M. Nguyen, Benedict C. Lau, Roxanne T. Vu
  • Patent number: 6330193
    Abstract: A method is described that compares two voltages, one of the voltages indicative of a data line voltage, a second of the voltages indicative of a reference voltage. An input signal is sent to each of a plurality of drivers where at least one of the drivers is coupled to the data line. The input signal is based upon the comparison. A bias is applied to a transistor from the input signal, the bias keeping the transistor in a high output impedance state when the two voltages are the same.
    Type: Grant
    Filed: March 31, 2000
    Date of Patent: December 11, 2001
    Assignee: Rambus, Inc.
    Inventors: Leung Yu, Roxanne T. Vu, Benedict C. Lau, Huy M. Nguyen, James A. Gasbarro