A Basic Study on a Very Low-Level DC Current Amplifier Using a Switched-Capacitor Circuit

Hiroki HIGA  Naoki NAKAMURA  Ikuo NAKAMURA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E88-A   No.6   pp.1394-1400
Publication Date: 2005/06/01
Online ISSN: 
DOI: 10.1093/ietfec/e88-a.6.1394
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Papers Selected from 2004 International Technical Conference on Circuits/Systems, Computers and Communications (ITC-CSCC 2004))
Category: 
Keyword: 
dc amplifier,  small current measurement,  negative feedback,  positive feedback,  switched-capacitor,  

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Summary: 
In order to miniaturize a very low-level dc current amplifier and to speed up its output response speed, we proposed to employ the switched-capacitor circuit (SCC) as its negative feedback circuit, instead of the conventionally used high-ohmage resistor. However, in the case of using SCC, the output waveform had unnecessary components. To decrease the effect of these components and to speed up the response speed, we used a switched-capacitor filter (SCF), an offset controller, and a positive feedback circuit. As a result, we demonstrated that it was useful to use the amplifier using the SCC.