Operational amplifier with self contained sample and hold and auto zero
US5258664A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 5, 1991 |
| Grant date | Nov 2, 1993 |
| Priority date | — |
| Expiry date | Jul 5, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/45479
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The switched capacitor amplifier circuit of the present invention employs a single amplifier with a built-in sample and hold and input auto zero. The built-in sample and hold of the present invention provides a continuously valid output in a multi-phase system. The present invention comprises a new auto zero configuration and a new amplifier. The new amplifier is referred to as the AZAMP. The circuit configuration of the AZAMP of the present invention comprises a two stage amplifier with switches added to the circuitry to provide the sample and hold function. By disconnecting the second stage during the hold mode, the output voltage will remain unchanged due to the voltage stored on a capacitor within the AZAMP. Charge cancelling circuitry is coupled to the sample and hold circuitry to cancel the charge injected onto said capacitor when the switch is turned off. The AZAMP of the present invention also has a self-contained auto zero function. The resulting benefits are reduced area consumption and low input equivalent offset.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.