Rail-to-Rail OTA Based on Signal Decomposition

Nobukazu TAKAI  Shigetaka TAKAGI  Nobuo FUJII  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E88-A   No.2   pp.424-430
Publication Date: 2005/02/01
Online ISSN: 
DOI: 10.1093/ietfec/e88-a.2.424
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
Category: 
Keyword: 
OTA,  rail-to-rail operation,  signal decomposition,  

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Summary: 
This paper proposes a rail-to-rail OTA. By adding a signal decomposing circuit at the input of given OTAs that have a limited input voltage range, a rail-to-rail OTA is obtained. Each decomposed input voltage signal is converted to a current signal by an OTA and each output current of OTAs is summed to obtain a linear output signal. Since the input signal is decomposed into small magnitude voltage signals, the OTAs used to the voltage-current conversion do not require a wide input-range and any OTA can be used to realize a rail-to-rail input voltage range OTA. HSPICE simulations are performed to verify the validity of the proposed method.