Patents by Inventor Peter H. R. Popplewell

Peter H. R. Popplewell 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).

  • Low-power class D amplifier using multistate analog feedback loops
    Patent number: 8553909
    Abstract: An audio amplifier system may include an audio CODEC/output (AOP) path featuring analog class-D amplifiers, and using Natural Sampling Pulse Width Modulation (PWM) to convert an analog input into a series of Rail-to-Rail pulses. The audio signal may be encoded in the average value of the PWM pulse train and may be recovered from the PWM signal by analog low pass filtering. The Class-D amplifiers may be designed with a negative feedback loop/network to compare the output signal with the input signal and suppress non-idealities introduced by the Class-D switching stage. Furthermore, operation of the AOP may be designed according to a separate signal transfer function and a separate noise transfer function, and 2nd order noise shaping may be performed at low power, with an optimized filter included in the feedback loop to achieve the best noise reduction at low power.
    Type: Grant
    Filed: April 29, 2011
    Date of Patent: October 8, 2013
    Assignee: SMSC Holdings S.A.R.L.
    Inventors: Justin L. Fortier, Ralph D. Mason, Renyuan Li, Christopher A. DeVries, Peter H. R. Popplewell, William Kung
  • Low-Power Class D Amplifier Using Multistate Analog Feedback Loops
    Publication number: 20120275493
    Abstract: An audio amplifier system may include an audio CODEC/output (AOP) path featuring analog class-D amplifiers, and using Natural Sampling Pulse Width Modulation (PWM) to convert an analog input into a series of Rail-to-Rail pulses. The audio signal may be encoded in the average value of the PWM pulse train and may be recovered from the PWM signal by analog low pass filtering. The Class-D amplifiers may be designed with a negative feedback loop/network to compare the output signal with the input signal and suppress non-idealities introduced by the Class-D switching stage. Furthermore, operation of the AOP may be designed according to a separate signal transfer function and a separate noise transfer function, and 2nd order noise shaping may be performed at low power, with an optimized filter included in the feedback loop to achieve the best noise reduction at low power.
    Type: Application
    Filed: April 29, 2011
    Publication date: November 1, 2012
    Applicant: SMSC Holdings S.a.r.l.
    Inventors: Justin L. Fortier, Ralph D. Mason, Renyuan Li, Christopher A. Devries, Peter H. R. Popplewell, William Kung