Differential amplifier with switched capacitor common mode feedback
US5838200A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 6, 1997 |
| Grant date | Nov 17, 1998 |
| Priority date | — |
| Expiry date | Jun 6, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45651
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential amplifier with switched capacitor common mode feedback includes a differential telescopic cascode amplifier in which the differential output terminals are individually coupled to a common mode input bias terminal via separate feedback capacitors. During a first time period (e.g., a sampling period), the output terminals are connected together via a pair of output switches to provide a common mode output voltage in response to a common mode input bias voltage applied to the bias terminal via an input switch. An operational amplifier compares the common mode output voltage to a common mode reference voltage and, based upon the difference between such voltages, generates the common mode input bias voltage. During a second time period (e.g., a holding period), the input and output switches are all opened and the output terminals provide a differential output voltage in response to a differential input signal applied to the differential input terminals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.