Power-off noise suppression circuit and associated methods for an audio amplifier device
US6954537B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 2001 |
| Grant date | Oct 11, 2005 |
| Priority date | — |
| Expiry date | Oct 10, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/348
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An audio amplifier device includes a power supply having an output for providing a supply voltage, a voltage divider connected to the output of the power supply for providing a divided supply voltage, and an audio amplifier that further includes a supply voltage rejection circuit. The audio amplifier has a first input for receiving an input audio signal, a second input for receiving the supply voltage, a third input for receiving a supply voltage rejection signal for the supply voltage rejection circuit, and an output for providing an output audio signal. A power-off noise suppression circuit has a first input for receiving the divided supply voltage and an output for providing the supply voltage rejection signal. The power-off noise suppression circuit sets the supply voltage rejection signal equal to the divided supply voltage during power-off of the power supply so that a rate of decrease of the supply voltage is greater than a rate of decrease of the supply voltage rejection signal for reducing noise in the output audio signal during the power-off.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.