High voltage, low-offset operational amplifier with rail-to-rail common mode input range in a digital CMOS process
US7064609B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 2004 |
| Grant date | Jun 20, 2006 |
| Priority date | — |
| Expiry date | Oct 16, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45681
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An operational amplifier with two differential pairs coupled to different current sources. The gate terminals of the transistors in the first differential pair are used as input terminals providing common mode input for most of the rail-to-rail voltage. The bulk terminals of the transistors in the second differential pair are used as input terminals providing common mode input for the remainder of the rail-to-rail voltage to thereby accomplish full rail-to-rail common mode. By using the bulk terminals of the field effect transistors in the second differential pair, rather than the gate terminals, as the input terminal, the operational amplifier may be constructing in a single well, thereby being compatible with standard digital CMOS processes. Alternatively, the bulk-driven transistors may be replaced with gate-driven depletion type transistors. The high voltage transistors in the output stage further reduce the offset voltage of the operational amplifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.