Amplifier offset cancellation using current copier
US6049246A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 11, 1998 |
| Grant date | Apr 11, 2000 |
| Priority date | — |
| Expiry date | Dec 11, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45188
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential amplifier circuit achieves offset cancellation by supplying an offset correction current from a current copier circuit to the output of the differential amplifier. The current copier is programmed by closing a first switch to short the differential input terminals of the amplifier, by opening a second switch to break the feedback loop of the amplifier, and by closing a third switch to allow the current copier to sense the offset output voltage at the output of the amplifier. The current copier generates an equal and opposite offset cancellation current which is summed with the offset current from the amplifier. The current copier circuit includes a storage capacitor for storing a voltage required to produce such offset cancellation current. After programming the storage capacitor, the third switch is opened, the first switch is opened, and the second switch is closed for normal operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.