Auto-zero amplifier circuit with wide dynamic range
US4276513A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 14, 1979 |
| Grant date | Jun 30, 1981 |
| Priority date | — |
| Expiry date | Sep 14, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/303
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An operational amplifier (33) is continuously switched back-and-forth between an auto-zero mode of operation and an accurate amplification mode of operation. During the auto-zero mode of operation, the junction between an offset voltage compensation (e.g., auto-zero) capacitor (35) and the noninverting input of the operational amplifier (33) is referenced to the input signal voltage via a bootstrap amplifier (31), rather than being tied to ground. Further, during the auto-zero mode of operation, the other end of the auto-zero capacitor (35) is referenced to the output of the operational amplifier (33), which is also connected to the inverting input of the operational amplifier. As a result, the auto-zero capacitor (35) is charged to a voltage level equal to the input offset voltage of the operational amplifier, but in polarity opposition thereto. During the accurate amplification mode of operation, the input signal is applied to the noninverting input of the operational amplifier (33) via the auto-zero capacitor (35). As a result, the charge on the auto-zero capacitor cancels the input offset voltage of the amplifier whereby the output of the operational amplifier (33) is accuratel…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.