High fidelity hearing aid amplifier
US5131046A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 1989 |
| Grant date | Jul 14, 1992 |
| Priority date | — |
| Expiry date | Nov 3, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2460/03
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A high fidelity hearing aid amplifier is operable at a very low battery voltage and includes a single integrated circuit chip which provides a variable gain amplifier and gain control circuitry operative at low signal levels to enhance gain at higher frequencies relative to gain at lower frequencies, such circuitry including a logarithmic rectifier arrangement and a peak detector in a compression ratio control circuit. Operation at a low battery voltage is enhanced through a compression ratio control circuit which provides a level shift between an AC output of the logarithmic rectifier arrangement and the peak detector. Current mirrors are provided to obtained balanced and stable operation, and an arrangement is provided for manual control by a user to obtain an optimum response characteristic.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.