Micropower amplifier/transducer driver with signal expansion
US5229721A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 1992 |
| Grant date | Jul 20, 1993 |
| Priority date | — |
| Expiry date | Apr 6, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An amplifier which combines the low quiescent current requirements of a Class B transistor amplifier with the minimal distortion qualities of a Class AB amplifier. In one disclosed embodiment the amplifier is utilized as a receiver amplifier and as a transmitter in a modular telephone adapter for coupling a telephone headset to a conventional modular telephone comprising a handset and a base unit. Signal expansion circuitry takes advantage of the dynamic emitter resistance of transistors in the amplifier's output stage through modulation of collector current in the output transistors and inverted phase summation of the resulting error signal with the input signal. DC bias circuitry supplies a current supply which is relatively insensitive to changes in power supply or device parameters. In one disclosed embodiment of the invention, two such amplifiers are utilized in a modular telephone headset adapter which allows a telephone headset and a telephone handset to be switchably connected to a telephone base unit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.