Variable gain amplifier having variable gain DC offset loop
US7695085B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 2007 |
| Grant date | Apr 13, 2010 |
| Priority date | — |
| Expiry date | Sep 17, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45728
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A variable gain amplifier and offset cancellation loop circuit and methods for tracking and correcting DC offset errors that may vary in accordance with the gain of the variable gain amplifier. The circuit is designed to provide tracking of rapid changes in the offset error while maintaining a desired overall frequency response of the combined variable gain amplifier and offset loop. The offset loop cancellation circuit has a wide enough bandwidth to allow the offset cancellation loop to track rapid changes in offset errors that result from rapid changes to the amplifier's gain setting. A control circuit is provided to prevent the large offset cancellation loop bandwidth from having a detrimental effect on the amplifier's overall bandwidth when the amplifier is set to high levels of forward gain by adjusting the offset cancellation loop gain as the forward gain of the amplifier is altered.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.