Switched-capacitor differential amplifier
US5142238A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 18, 1991 |
| Grant date | Aug 25, 1992 |
| Priority date | — |
| Expiry date | Jul 18, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/005
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The switched-capacitor differential amplifier circuit of the present invention employs a more efficient switched-capacitor network to provide a common mode range which is not limited by the amplifier power supply, and to achieve a high common mode rejection ratio at high frequencies with decreased sensitivity to component tolerances. The circuit employs a two-phase system, during the first phase of which, the circuit is auto-zeroed, the differential inputs are sampled and the capacitors are pre-charged. During the second phase, the differential inputs are disconnected and the bottom plates of the input capacitors are coupled together. The charge redistribution within the circuit forms an output potential that is proportional to the difference between the input signals, and that is offset by a user specified voltage. The present invention substantially eliminates the effects of parasitic capacitance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.