Patents by Inventor Jim Griffiths

Jim Griffiths 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).

  • Active bias network circuit for radio frequency amplifier
    Patent number: 6373339
    Abstract: A bias network for a radio frequency signal power amplifier. A current source is connected to a source of band gap voltage and produces a current proportional to the voltage. A reference voltage circuit receives the current and produces a voltage which is proportional to the current, as well as changes in temperature. An operational amplifier is used to connect the reference voltage to the power amplifier, so that the power amplifier is effectively isolated from the reference voltage circuit and current bearer circuit. A power amplifier breakdown protection circuit is connected across the output of the operational amplifier for diverting avalanche current produced form the power amplifier away from the power amplifier when the power amplifier output is mismatched through the antenna. Baseband signal transmission from the power amplifier to the bias network circuit is also significantly reduced, thus avoiding the generation of spurious radiation components.
    Type: Grant
    Filed: June 14, 2001
    Date of Patent: April 16, 2002
    Assignee: International Business Machines Corporation
    Inventors: Phillip Antognetti, Jim Griffiths, David Helms, James Moniz, Scott Munro, Joshua Park, Carl Stuebing, Xiangdong Zhang
  • Active bias network circuit for radio frequency amplifier
    Publication number: 20010054934
    Abstract: A bias network for a radio frequency signal power amplifier. A current source is connected to a source of band gap voltage and produces a current proportional to the voltage. A reference voltage circuit receives the current and produces a voltage which is proportional to the current, as well as changes in temperature. An operational amplifier is used to connect the reference voltage to the power amplifier, so that the power amplifier is effectively isolated from the reference voltage circuit and current bearer circuit. A power amplifier breakdown protection circuit is connected across the output of the operational amplifier for diverting avalanche current produced form the power amplifier away from the power amplifier when the power amplifier output is mismatched through the antenna. Baseband signal transmission from the power amplifier to the bias network circuit is also significantly reduced, thus avoiding the generation of spurious radiation components.
    Type: Application
    Filed: June 14, 2001
    Publication date: December 27, 2001
    Applicant: International Business Machines Corporation
    Inventors: Phillip Antognetti, Jim Griffiths, David Helms, James Moniz, Scott Munro, Joshua Park, Carl Stuebing, Xiangdong Zhang
  • Active bias network circuit for radio frequency amplifier
    Patent number: 6259324
    Abstract: A bias network for a radio frequency signal power amplifier. A current source is connected to a source of band gap voltage and produces a current proportional to the voltage. A reference voltage circuit receives the current and produces a voltage which is proportional to the current, as well as changes in temperature. An operational amplifier is used to connect the reference voltage to the power amplifier, so that the power amplifier is effectively isolated from the reference voltage circuit and current bearer circuit. A power amplifier breakdown protection circuit is connected across the output of the operational amplifier for diverting avalanche current produced form the power amplifier away from the power amplifier when the power amplifier output is mismatched through the antenna. Baseband signal transmission from the power amplifier to the bias network circuit is also significantly reduced, thus avoiding the generation of spurious radiation components.
    Type: Grant
    Filed: June 23, 2000
    Date of Patent: July 10, 2001
    Assignee: International Business Machines Corporation
    Inventors: Phillip Antognetti, Jim Griffiths, David Helms, James Moniz, Scott Munro, Joshua Park, Carl Stuebing, Xiangdong Zhang