Patents by Inventor Ralph A. Duncan

Ralph A. Duncan 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: 7053697
    Abstract: An integrated circuit formed on a semiconductor chip, comprising a low pass filter circuit having a first resistor of a first resistance value and a capacitor of a first capacitance value, wherein the first resistance value and the first capacitance value determine a corner frequency of the filter; and a tuning circuit having a second resistor of a second resistance value, a switched-capacitor of a third resistance value and a comparator that compares two voltage signals to produce a control signal, wherein the control signal adjusts the first and second resistance values as a function of the third resistance value. The corner frequency of the filter can be adjusted by varying one or more reference voltage signals. In combination, the corner frequency of the filter is adjusted by changing the frequency of a clock that controls the switched-capacitor to decrease the circuit sensitivity.
    Type: Grant
    Filed: April 13, 2005
    Date of Patent: May 30, 2006
    Assignee: Broadcom Corporation
    Inventors: Ralph A. Duncan, Chun-Ying Chen, Young J. Shin
  • Patent number: 6894557
    Abstract: An integrated circuit formed on a semiconductor chip, comprising a low pass filter circuit having a first resistor of a first resistance value and a capacitor of a first capacitance value, wherein the first resistance value and the first capacitance value determine a corner frequency of the filter; and a tuning circuit having a second resistor of a second resistance value, a switched-capacitor of a third resistance value and a comparator that compares two voltage signals to produce a control signal, wherein the control signal adjusts the first and second resistance values as a function of the third resistance value. The corner frequency of the filter can be adjusted by varying one or more reference voltage signals. In combination, the corner frequency of the filter is adjusted by changing the frequency of a clock that controls the switched-capacitor to decrease the circuit sensitivity.
    Type: Grant
    Filed: January 30, 2004
    Date of Patent: May 17, 2005
    Assignee: Broadcom Corporation
    Inventors: Ralph A. Duncan, Chun-Ying Chen, Young J. Shin
  • Publication number: 20040183589
    Abstract: An integrated circuit formed on a semiconductor chip, comprising a low pass filter circuit having a first resistor of a first resistance value and a capacitor of a first capacitance value, wherein the first resistance value and the first capacitance value determine a corner frequency of the filter; and a tuning circuit having a second resistor of a second resistance value, a switched-capacitor of a third resistance value and a comparator that compares two voltage signals to produce a control signal, wherein the control signal adjusts the first and second resistance values as a function of the third resistance value. The corner frequency of the filter can be adjusted by varying one or more reference voltage signals. In combination, the corner frequency of the filter is adjusted by changing the frequency of a clock that controls the switched-capacitor to decrease the circuit sensitivity.
    Type: Application
    Filed: January 30, 2004
    Publication date: September 23, 2004
    Applicant: Broadcom Corporation
    Inventors: Ralph A. Duncan, Chun-Ying Chen, Young J. Shin
  • Patent number: 6710644
    Abstract: An integrated circuit formed on a semiconductor chip, comprising a low pass filter circuit having a first resistor of a first resistance value and a capacitor of a first capacitance value, wherein the first resistance value and the first capacitance value determine a corner frequency of the filter; and a tuning circuit having a second resistor of a second resistance value, a switched-capacitor of a third resistance value and a comparator that compares two voltage signals to produce a control signal, wherein the control signal adjusts the first and second resistance values as a function of the third resistance value. The corner frequency of the filter can be adjusted by varying one or more reference voltage signals. In combination, the corner frequency of the filter is adjusted by changing the frequency of a clock that controls the switched-capacitor to decrease the circuit sensitivity.
    Type: Grant
    Filed: November 29, 2001
    Date of Patent: March 23, 2004
    Assignee: Broadcom Corporation
    Inventors: Ralph A. Duncan, Chun-Ying Chen, Young J. Shin
  • Publication number: 20020190783
    Abstract: An integrated circuit formed on a semiconductor chip, comprising a low pass filter circuit having a first resistor of a first resistance value and a capacitor of a first capacitance value, wherein the first resistance value and the first capacitance value determine a comer frequency of the filter; and a tuning circuit having a second resistor of a second resistance value, a switched-capacitor of a third resistance value and a comparator that compares two voltage signals to produce a control signal, wherein the control signal adjusts the first and second resistance values as a function of the third resistance value. The corner frequency of the filter can be adjusted by varying one or more reference voltage signals. In combination, the comer frequency of the filter is adjusted by changing the frequency of a clock that controls the switched-capacitor to decrease the circuit sensitivity.
    Type: Application
    Filed: November 29, 2001
    Publication date: December 19, 2002
    Applicant: Broadcom Corporation.
    Inventors: Ralph A. Duncan, Chun-Ying Chen, Young J. Shin