Electret microphone circuit with low battery disable
US6266424A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1997 |
| Grant date | Jul 24, 2001 |
| Priority date | — |
| Expiry date | Nov 12, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/6033
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A battery circuit for coupling a battery source to an electret microphone. The circuit includes impedance circuitry for providing appropriate bias impedance for a desired microphone sensitivity, and disconnect circuitry for automatically disconnecting the battery source from the electret microphone in response to detecting a low voltage state in order to prevent distortion and low output level of the microphone. In an alternative embodiment of the invention there is provided second impedance circuitry for driving corresponding inputs with minimal loss. In another alternative embodiment of the invention there is provided a compensation circuit which operates to extend battery source life and prevent lower output at lower voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.