Amplificador de instrumentação em modo corrente com entrada e saída rail-to-rail

• Ano de defesa: 2009
• Autor(a) principal: Vieira, Filipe Costa Beber
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; BR; Ciência da Computação; UFSM; Programa de Pós-Graduação em Informática
• Palavras-chave em Português: Circuitos integrados analógicos; Amplificador de instrumentação em modo corrente; Faixa de entrada em modo comum; Taxa de rejeição em modo comum; Amplificador rail-to-rail; Analog integrated circuits; Current mode instrumentation amplifier; Common mode input range; Common mode rejection ration; Rail-to-rail amplifier; CNPQ::CIENCIAS EXATAS E DA TERRA::CIENCIA DA COMPUTACAO
• Link de acesso: http://repositorio.ufsm.br/handle/1/5347

This dissertation is aimed at the development of a current mode instrumentation amplifier (CMIA) with a high common mode input range. This characteristic is obtained due to the rail-to-rail operational amplifiers (opamps). These opamps are built with rail-to-rail differential amplifiers as input stages, and with cascode-based output stages, which are able to copy its current by adding identical branches and connecting their gates without the voltage degradation as the known CMIA topologies. The main contribution of this work is the development of a rail-to-rail current mode instrumentation amplifier, analyzing the pros and cons of this topology. The functionality of the proposed topology is shown through measured results of a manufactured integrated circuit. This first prototype, although it was operated in a large input common mode range, presented insufficient values of CMRR (Common Mode Rejection Ratio) and VOS (Offset voltage). These two characteristics were studied and modeled, the instrumentation amplifier was re-designed, and simulated results demonstrate important improvements.