DocumentCode :
3012985
Title :
Rail-to-rail CMOS opamp with stabilized operating point
Author :
Gärtner, Peter ; Richter, Harald
Author_Institution :
Dept. of Electron Devices, Budapest Univ. of Technics & Econ., Budapest, Hungary
fYear :
2010
fDate :
4-6 Oct. 2010
Firstpage :
99
Lastpage :
102
Abstract :
The paper presents a new solution to achieve rail-to-rail common mode input voltage swing for CMOS operational amplifiers. The common mode input range of a MOS differential stage is limited by the threshold voltage of the input transistors. With a pair of complementary input stages the whole range from GND to VDD can be covered. Their drain currents are summed up but the resulting current as well as the DC voltage of the summing node drastically change when one of the input stages turns off near the power rails. The new method applies a built-in feedback loop with an auxiliary opamp for stabilizing the voltage at the summing node. This way a very stable operating point and ideal CMRR can be assured. With selected transistor aspect ratios nearly constant voltage gain can be achieved for the whole common mode input voltage range.
Keywords :
CMOS analogue integrated circuits; circuit feedback; operational amplifiers; transistors; CMOS operational amplifiers; DC voltage; MOS differential stage; auxiliary opamp; built-in feedback loop; constant voltage gain; drain currents; input transistors; rail-to-rail CMOS OpAmp; rail-to-rail common mode input voltage swing; stabilized operating point; CMOS integrated circuits; Impedance; Integrated circuit modeling; Mirrors; Rail to rail amplifiers; Transistors; Voltage control;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electronics Conference (BEC), 2010 12th Biennial Baltic
Conference_Location :
Tallinn
ISSN :
1736-3705
Print_ISBN :
978-1-4244-7356-4
Electronic_ISBN :
1736-3705
Type :
conf
DOI :
10.1109/BEC.2010.5631558
Filename :
5631558
Link To Document :
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