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ENIDH – EEM - Artigo Científico

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http://hdl.handle.net/10400.26/49149

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Percorrer ENIDH – EEM - Artigo Científico por assunto "Biomedical"

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  • A new family of CMOS inverter based OTAs for Biomedical and Healthcare Applications
    Publication . Póvoa, Ricardo; Canelas, António; Martins, Ricardo; Lourenço, Nuno; Horta, Nuno; Goes, João
    This paper presents a new family of innovative operational transconductance amplifier (OTA) topologies based on CMOS inverter structures, with improved gain and energy-efficiency. This new family of OTA designs is suitable for biomedical and healthcare circuits and systems, due to the high energy-efficiency, improved gain and low level of noise contribution, when compared to the state-of-the-art in this field. In this paper, two fully-differential implementations are presented, a first one with a double CMOS branch biased by two pairs of voltage-combiners structures in both NMOS and PMOS configurations, and a second one with folded voltage-combiners specifically targeting low voltage applications, e.g., supplies below 1 V. The usage of voltage-combiners to bias the OTAs improves the gain and the gain-bandwidth product, therefore improving the energy-efficiency figure-of-merit. High values of figure-of-merit are achieved in both implementations, i.e., more than 1600 MHz × pF/mA and 2000 MHz × pF/mA, gain values above 53 dB and 50 dB under supply sources of 2 V and 0.7 V respectively. The folded voltage-combiners biased OTA is able to operate correctly under a voltage supply down to 0.7 V with proper DC biasing. The results are finally compared with state-of-the-art in this field and the potential of the circuits is fulfilled using a state-of-the-art layout-aware integrated-circuit optimization framework, AIDA, particularly relevant in order to overcome the device stacking problematic for lower voltages.
    2020-03Artigo científico Acesso restrito Ver mais
  • Sub- μW Tow-Thomas Based Biquad Filter with Improved Gain for Biomedical Applications
    Publication . Póvoa, R.; Arya, R.; Canelas, A.; Passos, F.; Martins, R.; Lourenço, N.; Horta, N.
    This paper presents an innovative topology of a gm-C Operational Transconductance Amplifier (OTA), with improved gain and energy-efficiency and its corresponding implementation inside a second order Tow-Thomas based filter configuration, for biomedical and healthcare applications. The proposed OTA architecture takes advantage of a current division technique, as well as the usage of a pair of cross-coupled voltage-combiners in replacement of the static current source that traditionally bias the differential pair. The circuitry proposed in this paper is described at analytical level, fully-designed at sizing level and validated at simulation level compounded by Monte Carlo results, using a standard 130 ​nm technology node. Both the OTA and the biquad filter architecture are compared, in terms of performance indexes, with state-of-the-art bibliography, where the potential of both is demonstrated. The designed filter operates at weak inversion and sub-threshold, being supplied by a 0.9 ​V source, achieving a cut-off frequency of 15 ​Hz, a gain of 7 ​dB, hence improving the input-referred noise and consuming nearly 0.55 ​μW.
    2020-01Artigo científico Desconhecido Ver mais