Abstract
A novel offset and finite-gain compensated differential switched-capacitor(SC) amplifier is presented. Incorporating the correlated double sampling (CDS) technique and input correlated level shifting (CLS) technique together, the DC offset and DC gain error of SC amplifier are further reduced by a factor of op-amp DC gain compared with the conventional offset and finite-gain compensated SC amplifier. The effectiveness of the new scheme has been analyzed and verified by extensive simulations. An SC amplifier with the proposed scheme is designed in 130 nm CMOS technology. Simulated results show that with an op-amp having a low DC gain of 30 dB and an input offset of 10 mV, the proposed SC amplifier achieves an output offset and DC-gain error of 154 µV and 0.05%, respectively, which are significantly improved compared with 1.155 mV and 0.42% achieved in the conventional SC amplifier.
Highlights
The switched-capacitor (SC) amplifier is widely used in various low-power, high-precision analog circuits, such as sample-and-hold circuits [1,2], instrumentation amplifiers for intelligent sensors in strain, pressure and temperature measurement [3], micro-electromechanical systems (MEMS) capacitive accelerometers [4], multi-parameter sensing micro-systems [5], and readout amplifiers for biomedical signal acquisition systems [6,7,8]
10 mV, the proposed SC amplifier achieves an output offset and DC-gain error of 154 μV and 0.05%, respectively, which are significantly improved compared with 1.155 mV and 0.42% achieved in the conventional SC amplifier
With the correlated double sampling (CDS) switching of the input capacitor and an output capacitor, the DC gain error is reduced and proportional to A−2, and the output DC offset is reduced by a factor of A, where A is the DC gain of the op-amp
Summary
The switched-capacitor (SC) amplifier is widely used in various low-power, high-precision analog circuits, such as sample-and-hold circuits [1,2], instrumentation amplifiers for intelligent sensors in strain, pressure and temperature measurement [3], micro-electromechanical systems (MEMS) capacitive accelerometers [4], multi-parameter sensing micro-systems [5], and readout amplifiers for biomedical signal acquisition systems [6,7,8] Those amplifiers should have a very low DC offset and DC gain error as the output signals detected by the sensors are low-frequency and low-level.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
