Digital compensation of analog volume control gain in a digital audio amplifier
US8126164B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 2006 |
| Grant date | Feb 28, 2012 |
| Priority date | — |
| Expiry date | Dec 29, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/3089
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.