Three-step ramped reference to reduce popping noises on audio circuit
US6775387B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1999 |
| Grant date | Aug 10, 2004 |
| Priority date | — |
| Expiry date | Nov 30, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R3/007
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Provided is a method (500) and audio circuit (100) for reducing popping noise in a load (140, 145) connected to the audio circuit, especially during audio circuit start-up. The method applies a time varying voltage (364) to the load that has a smooth, S-shaped curve when plotted over time. The device include an integrated circuit (IC) set as a channel block (110), a load connected between the channel block and ground, a bypass control (150) connected to the channel block for producing a controlled ground reference voltage having an S-shaped curve to the channel block, a shunt control (170) controlling the voltage delivered across the load, and a ground capacitor (160) coupled between the bypass control and ground. The channel block typically includes an amplifier which supplies the output voltage across the load. The bypass circuit generally includes a bypass generator and a transistor selectively providing a charge to the ground capacitor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.