Minimizing switching noise and its effects in auto-zeroed amplifiers
US7382183B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 2007 |
| Grant date | Jun 3, 2008 |
| Priority date | — |
| Expiry date | Jul 9, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/45986
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Two nulling amplifiers are used with an auto-zeroed differential amplifier. While one nulling amplifier is compensating the main amplifier, the other nulling amplifier is being zeroed for both differential mode (DM) and common mode (CM) offsets. By using two nulling amplifiers, one always connected to the main amplifier, a relatively constant open-loop gain is maintained for the main amplifier. A further improvement is make-before-break timing overlap of the switch operations between the two nulling amplifiers and the main amplifier. This ensures that the main amplifier is continuously driven by one or both null amplifiers, thereby maintaining a low impedance at the main amplifier auxiliary port. Both DM and CM offset sampling and precharging of each of the two nulling amplifiers is performed so as to substantially reduce switching glitches in the output of the main amplifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.