Operational amplifier having a common mode feedback circuit portion
US8283981B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 5, 2011 |
| Grant date | Oct 9, 2012 |
| Priority date | — |
| Expiry date | May 5, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45404
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An operational amplifier that can suppress lowering of the current driving capability while performing a self adjustment of the common mode voltage is disclosed. A common mode voltage adjusting transistor and an auxiliary transistor are connected in parallel with a low-voltage side drive transistor of each of push-pull amplifying circuits that produce first and second amplified difference signals having different polarities in accordance with drive signals obtained by level-shifting a difference signal indicating a difference value of the levels of the first and second input signals by predetermined values. Current drive capabilities during a period of outputting said first and second amplified difference signals and a common mode voltage adjusting period respectively are increased by driving said auxiliary drive transistor by alternately using the drive signal obtained by level-shifting the difference signal and a common mode voltage adjusting signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.