Method and apparatus for adjusting the common-mode output voltage of a sample-and-hold amplifier
US5914638A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 6, 1997 |
| Grant date | Jun 22, 1999 |
| Priority date | — |
| Expiry date | Jun 6, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/45977
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A fully differential sample-and-hold amplifier 60 includes a common-mode feedback circuit 100 for adjusting the common-mode input so that the common-mode output remains near a desired level. During a first switching state, the sample-and-hold amplifier samples voltages and is coupled to the feedback circuit 100 for the adjustment of the common-mode input level. During a second switching state, sample-and-hold amplifier performs its charge transfer and amplification function while the feedback circuit 100 is not coupled to the sample-and-hold amplifier. During the first switching state, the feedback circuit 100 receives as an input the common-mode voltage of the operational amplifier and outputs an amplification of the difference between the common-mode voltage and a regulating input voltage. The output of the sample-and-hold amplifier is coupled to the common-mode input of the operational amplifier. In this manner, differences between the common-mode voltage of the operational amplifier and the regulating voltage are used to adjust the common-mode input of the operational amplifier so that the common-mode output of the operational amplifier approximates the regulating voltage. The …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.