The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 08, 2013
Filed:
Apr. 29, 2011
Justin L. Fortier, Carleton Place, CA;
Ralph D. Mason, Ottawa, CA;
Renyuan LI, Ottawa, CA;
Christopher A. Devries, Ottawa, CA;
Peter H. R. Popplewell, Ottawa, CA;
William Kung, Stittsville, CA;
Justin L. Fortier, Carleton Place, CA;
Ralph D. Mason, Ottawa, CA;
Renyuan Li, Ottawa, CA;
Christopher A. DeVries, Ottawa, CA;
Peter H. R. Popplewell, Ottawa, CA;
William Kung, Stittsville, CA;
SMSC Holdings S.A.R.L., Luxembourg, LU;
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 2order 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. Operation of the amplifier feedback network may be similar to that of a continuous time, low-pass delta-sigma modulator, but with a PWM loop wrapped around the class-D power amplifier.