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:
Feb. 28, 2012
Filed:
Nov. 29, 2006
Anker Bjorn-josefsen, Lynge, DK;
David E. Zaucha, Carrollton, TX (US);
Thomas Morch, Soborg, DK;
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A digital audio system including a combination of analog and digital volume control is disclosed. A variable power supply voltage biases a power amplifier for each channel, and applies a bias voltage corresponding to an analog volume control signal. In one disclosed embodiment, digital gain control circuitry compares the bias voltage with the level expected for the analog volume control signal; if the bias voltage has not dropped in response to a reduction in the analog volume control signal, the digital gain control circuitry reduces the digital gain of the input digital audio signal, until the bias voltage responds to the reduced volume. In another disclosed embodiment, modeling or characterization of the audio system is used to derive a digital gain control signal based on the desired volume signal and the amplitude of the digital audio signal itself. In another disclosed embodiment, a slew rate limiter slows the rate of change of the control signal applied to the variable power supply, in which case the slowed control signal is used in the comparison or calculations of the reduced digital gain.