Differential amplifier and high frequency resonant circuits constructed therefrom
US5185581A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 26, 1992 |
| Grant date | Feb 9, 1993 |
| Priority date | — |
| Expiry date | Mar 26, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B2201/02
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential amplifier includes a bias current source and a current dividing circuit for controllably dividing a bias current between first and second current paths. A first pair of matched transistors is connected as a differential pair between matched load impedances and the first current path. A second pair of matched transistors is connected as a differential pair between the matched load impedances and the second current path. Differential inputs of the second differential pair are connected to corresponding differential inputs of the second differential pair. The transistors of the first and second pairs have different emitter areas. Matched capacitors may be connected between respective differential inputs and differential outputs of the differential amplifier. The load impedances may be tapped to provide outputs having a lower differential gain. The differential amplifier is useful for building resonant circuits, for example voltage controlled oscillators having high Q factors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.