Quiet power up and power down of a digital audio amplifier
US7312654B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2005 |
| Grant date | Dec 25, 2007 |
| Priority date | — |
| Expiry date | Mar 15, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/351
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A closed loop audio amplifier system and method of powering up/down the system without producing audible artifacts are provided. During power up, a prebias voltage is provided to each output connected to a speaker to increase the voltage to a nominal output level. High impedance switches are then driven at a 50% duty cycle. Feedback from the output is supplied to a servo, which is enabled to fine tune the output voltage. Low impedance switches are then driven at a 50% duty cycle at a quarter cycle timing. The order of the feedback loop depends on which of the high or low impedance switches are driven. The prebias voltage is then removed before audio signals to be amplified are supplied to the system. Timing of driving of the switches is programmable. To power down, essentially the reverse sequence is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.