Circuit comprising means for reducing the DC-offset and the noise produced by an amplifier
US6262626A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1999 |
| Grant date | Jul 17, 2001 |
| Priority date | — |
| Expiry date | Nov 12, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/81
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An amplifier (AMP) is provided with a pair of choppers (CHP.sub.i,CHP.sub.o) in order to reduce the DC-offset and the noise produced by the amplifier (AMP). To obtain an optimal noise reduction the pair of choppers (CHP.sub.i,CHP.sub.o) operate on a high frequency. As a result the DC-offset cancellation is not optimal because a so-called charge injection of the switches in the pair of choppers (CHP.sub.i,CHP.sub.o) produces a DC-offset. To overcome this problem the amplifier (AMP) is further provided with further offset cancellation means which are for example formed by a further pair of choppers (CHP.sub.fi,CHP.sub.fo). This further pair of choppers (CHP.sub.fi,CHP.sub.fo) operates on a relatively low frequency. The combination of the pair of choppers (CHP.sub.i,CHP.sub.o) and the further pair of choppers (CHP.sub.fi,CHP.sub.fo) guarantees an optimal DC-offset cancellation as well as an optimal noise cancellation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.