Gain cell with digital control
US4885547A · kind A · utility
9Cited by
1References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1988 |
| Grant date | Dec 5, 1989 |
| Priority date | — |
| Expiry date | Jul 7, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G1/0023
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential amplifier in the form of a Gilbert gain cell is controlled by a pair of input currents applied to a pair of differentially coupled transistor pairs. A digital signal is generated and input into a CMOS digital-to-analog converter (DAC). The DAC outputs a pair of currents on conductors which are maintained at virtual ground by the use of a current mirror and an operational amplifier. The control signals applied to the differentially coupled transistor pairs are generated as base currents of transistors conducting the DAC output currents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.