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Author: search.filters.author.Torteanchai, UsaSubject: search.filters.subject.Operational transconductance amplifier

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    16-nW 0.5-V low-pass filter for bio-signal applications
    (2025-01-01)
    Phatsornsiri, Punnavich
    ;
    Kumngern, Montree
    ;
    Khateb, Fabian
    ;
    Torteanchai, Usa
    ;
    Wongprommoon, Natapong
    A low-voltage, ultra-low power fully differential low-pass filter for bio-signal applications using multiple-input fully differential operational transconductance amplifiers (OTA) is presented in this article. The multiple inputs of OTA can be achieved using multiple-input dynamic threshold MOS transistor (MIDT-MOST) technique. The novelty of this work is to exhibit the proposed filter using multiple-input OTAs, which leads to a reduction in the number of active OTAs and power consumption. The fourth-order low-pass filter that is cascaded by two second-order filters has been presented. The fourth-order low-pass filter is designed and simulated in the Cadence environment using the 0.18 μm CMOS technology from TSMC at a supply voltage of 0.5 V. The simulation results show that the filter consumes 16 nW of power at a bandwidth of 110 Hz, has a total harmonic distortion (THD) of 1 % at 204.96 mV input amplitude, and provides dynamic range of 69.24 dB. These results indicate that the proposed low-pass filter can be applied to bio-signal processing applications.
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    Programmable Universal Filter and Quadrature Oscillator Using Single Output Operational Transconductance Amplifiers
    (2021-01-01)
    Knobnob, Boonying
    ;
    Torteanchai, Usa
    ;
    Kumngern, Montree
    This paper presents a new programmable universal filter and quadrature oscillator based on the single output operational transconductance amplifiers (OTAs). The proposed universal filter and quadrature oscillator can be achieved into single topology by programming analog switches. When the circuit performs as a universal filter, it can realize low-pass, high-pass, band-pass, band-stop and all-pass filters with orthogonal and electronic controls of the natural frequency and quality factor. When the circuit performs as a quadrature oscillator, it provides a three-phase quadrature output signal which the condition and frequency of oscillations can be controlled orthogonally and electronically. The proposed structure can be realized based on the single output OTAs which are easily implemented as both commercially available integrated circuits (ICs) as OTAs and complementary metal-oxide semiconductor (CMOS) OTAs as IC forms. SPICE simulation using standard 0.18 µm CMOS process is used for investigating the performance of the proposed circuit whereas the workability of new circuit is confirmed by LM13600 discrete-component integrated circuits as OTAs.
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    Versatile electronically tunable voltage-mode filter based on simple CMOS OTAs
    (2017-12-01)
    Torteanchai, Usa
    ;
    Yutthanaboon, Sathian
    ;
    Sarsitthithum, Kanok
    ;
    Kumngern, Montree
    In this paper, a new versatile electronically controllable voltage-mode biquadratic filter with four inputs and three outputs based on simple CMOS operational transconductance amplifiers (OTAs) is presented. By appropriately selecting the input and output terminals, the proposed filter can work as either a single-input multiple-output (SIMO) or a multiple-input single-output (MISO) biquadratic filter without changing the circuit topology. When it is a function of SIMO filter, the circuit provides band-pass (BP), low-pass (LP) and band-stop (BS) voltage responses and using grounded capacitors. The all-pass (AP) and high-pass (HP) voltage responses can be obtained using addition and subtraction circuits. Continually, when it is a function of MISO filter, the circuit can realize five standard non-inverting and inverting filtering functions such as LP, BP, HP, BS and AP filters. Both the circuit functions offer an electronic control of the natural frequency through adjusting the bias currents of OTAs. The filters are absent from active and passive component-matching condition and invertingtype input signal requirements for realizing all filtering responses. The passive and active sensitivities are low. The performances of the proposed filter can be confirmed by PSPICE simulation results.
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    OTA-Based current square-rooting circuit
    (2017-02-01)
    Kumngern, Montree
    ;
    Torteanchai, Usa
    This paper presents a new simple current-mode square-rooting circuit based on CMOS technology. The proposed circuit consists of only one CMOS operational transconductance amplifier (OTA) with source degeneration and one MOS transistor. The input signal of the circuit is a current and the output is a current proportional to the square root of the input current with high-output impedance level. OTA with source degeneration is used to provide wide input dynamic range. The circuit also exhibits wide bandwidth and good temperature stability. PSPICE simulation results are used to demonstrate the performance of the proposed square-rooting circuit.