Variable gain amplifier with low phase variation
US7332967B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 2005 |
| Grant date | Feb 19, 2008 |
| Priority date | — |
| Expiry date | Jan 12, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45362
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A VGA is provided that is designed to reduce or even eliminate entirely variations in phase response/shift with changes in gain. Compensation is made for parasitic capacitances of elements in the VGA that would otherwise cause variation in phase with changes in gain. An additional capacitance is introduced to the VGA to compensate for the sources of the parasitic capacitance. The technique for introducing the additional capacitance depends on the source of the parasitic capacitance being treated. The additional capacitance is introduced to one or more of transistor amplifier circuits in the VGA, wherein each transistor amplifier circuit has a different gain and one of the transistor amplifier circuits is selected depending on the desired gain of the VGA. These compensation techniques equalize the phase response of the transistor amplifier circuits (each having a different gain) so that regardless of which transistor amplifier circuit is selected, the phase shift will be substantially the same. These techniques may be applied to each VGA stage of a multi-stage VGA system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.