Fully differential switched capacitor amplifier having autozeroed common-mode feedback
US4697152A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 11, 1986 |
| Grant date | Sep 29, 1987 |
| Priority date | — |
| Expiry date | Apr 11, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/0278
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A fully differential amplifier which is compensated for both input offset voltage error and output common-mode variation is provided. The differential amplifier provides two very accurate output reference voltages which vary in proportion to the difference between first and second input voltages. In one form, the differential amplifier functions as an integrator. A differential amplifier is provided which uses first and second input pairs of differential transistors for normal differential operation and for common-mode output voltage regulation, respectively. Both input pairs of transistors must be compensated for offset voltage associated therewith. A compensation portion external to the differential amplifier is used to compensate for an offset voltage associated with circuitry within the differential amplifier for regulating the common-mode output voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.