208 research outputs found

    Low Voltage Low Power Analogue Circuits Design

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    DisertačnĂ­ prĂĄce je zaměƙena na vĂœzkum nejbÄ›ĆŸnějĆĄĂ­ch metod, kterĂ© se vyuĆŸĂ­vajĂ­ pƙi nĂĄvrhu analogovĂœch obvodĆŻ s vyuĆŸitĂ­ nĂ­zkonapěƄovĂœch (LV) a nĂ­zkopƙíkonovĂœch (LP) struktur. Tyto LV LP obvody mohou bĂœt vytvoƙeny dĂ­ky vyspělĂœm technologiĂ­m nebo takĂ© vyuĆŸitĂ­m pokročilĂœch technik nĂĄvrhu. DisertačnĂ­ prĂĄce se zabĂœvĂĄ prĂĄvě pokročilĂœmi technikami nĂĄvrhu, pƙedevĆĄĂ­m pak nekonvenčnĂ­mi. Mezi tyto techniky patƙí vyuĆŸitĂ­ prvkĆŻ s ƙízenĂœm substrĂĄtem (bulk-driven - BD), s plovoucĂ­m hradlem (floating-gate - FG), s kvazi plovoucĂ­m hradlem (quasi-floating-gate - QFG), s ƙízenĂœm substrĂĄtem s plovoucĂ­m hradlem (bulk-driven floating-gate - BD-FG) a s ƙízenĂœm substrĂĄtem s kvazi plovoucĂ­m hradlem (quasi-floating-gate - BD-QFG). PrĂĄce je takĂ© orientovĂĄna na moĆŸnĂ© zpĆŻsoby implementace znĂĄmĂœch a modernĂ­ch aktivnĂ­ch prvkĆŻ pracujĂ­cĂ­ch v napěƄovĂ©m, proudovĂ©m nebo mix-mĂłdu. Mezi tyto prvky lze začlenit zesilovače typu OTA (operational transconductance amplifier), CCII (second generation current conveyor), FB-CCII (fully-differential second generation current conveyor), FB-DDA (fully-balanced differential difference amplifier), VDTA (voltage differencing transconductance amplifier), CC-CDBA (current-controlled current differencing buffered amplifier) a CFOA (current feedback operational amplifier). Za Ășčelem potvrzenĂ­ funkčnosti a chovĂĄnĂ­ vĂœĆĄe zmĂ­něnĂœch struktur a prvkĆŻ byly vytvoƙeny pƙíklady aplikacĂ­, kterĂ© simulujĂ­ usměrƈovacĂ­ a induktančnĂ­ vlastnosti diody, dĂĄle pak filtry dolnĂ­ propusti, pĂĄsmovĂ© propusti a takĂ© univerzĂĄlnĂ­ filtry. VĆĄechny aktivnĂ­ prvky a pƙíklady aplikacĂ­ byly ověƙeny pomocĂ­ PSpice simulacĂ­ s vyuĆŸitĂ­m parametrĆŻ technologie 0,18 m TSMC CMOS. Pro ilustraci pƙesnĂ©ho a ĂșčinnĂ©ho chovĂĄnĂ­ struktur je v disertačnĂ­ prĂĄci zahrnuto velkĂ© mnoĆŸstvĂ­ simulačnĂ­ch vĂœsledkĆŻ.The dissertation thesis is aiming at examining the most common methods adopted by analog circuits' designers in order to achieve low voltage (LV) low power (LP) configurations. The capability of LV LP operation could be achieved either by developed technologies or by design techniques. The thesis is concentrating upon design techniques, especially the non–conventional ones which are bulk–driven (BD), floating–gate (FG), quasi–floating–gate (QFG), bulk–driven floating–gate (BD–FG) and bulk–driven quasi–floating–gate (BD–QFG) techniques. The thesis also looks at ways of implementing structures of well–known and modern active elements operating in voltage–, current–, and mixed–mode such as operational transconductance amplifier (OTA), second generation current conveyor (CCII), fully–differential second generation current conveyor (FB–CCII), fully–balanced differential difference amplifier (FB–DDA), voltage differencing transconductance amplifier (VDTA), current–controlled current differencing buffered amplifier (CC–CDBA) and current feedback operational amplifier (CFOA). In order to confirm the functionality and behavior of these configurations and elements, they have been utilized in application examples such as diode–less rectifier and inductance simulations, as well as low–pass, band–pass and universal filters. All active elements and application examples have been verified by PSpice simulator using the 0.18 m TSMC CMOS parameters. Sufficient numbers of simulated plots are included in this thesis to illustrate the precise and strong behavior of structures.

    Review on Design of OTA Using Non-Conventional Analog Techniques

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    The OTA is an amplifier whose differential input voltage produces an output current. Thus, it is a voltage controlled current source. Operational transconductance amplifier is one of the most significant building-blocks in integrated continuous-time filters. A review of various non-conventional analog design techniques has been done in this paper. Several previous works have been studied and their comparison on various performance parameters is shown. This paper starts with the introduction of OTA, followed by the discussion on various OTA design techniques along with their block diagram in addition to advantages and disadvantages of these techniques. Two comparative tables are shown at the end

    0.3-Volt Rail-to-Rail DDTA and Its Application in a Universal Filter and Quadrature Oscillator

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    This paper presents the extremely low-voltage supply of the CMOS structure of a differential difference transconductance amplifier (DDTA). With a 0.3-volt supply voltage, the circuit offers rail-to-rail operational capability. The circuit is designed for low-frequency biomedical and sensor applications, and it consumes 357.4 nW of power. Based on two DDTAs and two grounded capacitors, a voltage-mode universal filter and quadrature oscillator are presented as applications. The universal filter possesses high-input impedance and electronic tuning ability of the natural frequency in the range of tens up to hundreds of Hz. The total harmonic distortion (THD) for the band-pass filter was 0.5% for 100 mV(pp) @ 84.47 Hz input voltage. The slight modification of the filter yields a quadrature oscillator. The condition and the frequency of oscillation are orthogonally controllable. The frequency of oscillation can also be controlled electronically. The THD for a 67 Hz oscillation frequency was around 1.2%. The circuit is designed and simulated in a Cadence environment using 130 nm CMOS technology from United Microelectronics Corporation (UMC). The simulation results confirm the performance of the designed circuits

    Utilizing Unconventional CMOS Techniques for Low Voltage Low Power Analog Circuits Design for Biomedical Applications

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    Tato disertačnĂ­ prĂĄce se zabĂœvĂĄ navrĆŸenĂ­m nĂ­zkonapěƄovĂœch, nĂ­zkopƙíkonovĂœch analogovĂœch obvodĆŻ, kterĂ© pouĆŸĂ­vajĂ­ nekonvenčnĂ­ techniky CMOS. LĂ©kaƙskĂĄ zaƙízenĂ­ na bateriovĂ© napĂĄjenĂ­, jako systĂ©my pro dlouhodobĂœ fyziologickĂœ monitoring, pƙenosnĂ© systĂ©my, implantovatelnĂ© systĂ©my a systĂ©my vhodnĂ© na noĆĄenĂ­, musĂ­ bĂœt male a lehkĂ©. Kromě toho je nutnĂ©, aby byly tyto systĂ©my vybaveny bateriĂ­ s dlouhou ĆŸivotnostĂ­. Z tohoto dĆŻvodu pƙevlĂĄdajĂ­ v biomedicĂ­nskĂœch aplikacĂ­ch tohoto typu nĂ­zkopƙíkonovĂ© integrovanĂ© obvody. NekonvenčnĂ­ techniky jako napƙ. vyuĆŸitĂ­ transistorĆŻ s ƙízenĂœm substrĂĄtem (Bulk-Driven “BD”), s plovoucĂ­m hradlem (Floating-Gate “FG”), s kvazi plovoucĂ­m hradlem (Quasi-Floating-Gate “QFG”), s ƙízenĂœm substrĂĄtem s plovoucĂ­m hradlem (Bulk-Driven Floating-Gate “BD-FG”) a s ƙízenĂœm substrĂĄtem s kvazi plovoucĂ­m hradlem (Bulk-Driven Quasi-Floating-Gate “BD-QFG”), se v nedĂĄvnĂ© době ukĂĄzaly jako efektivnĂ­ prostƙedek ke zjednoduĆĄenĂ­ obvodovĂ©ho zapojenĂ­ a ke snĂ­ĆŸenĂ­ velikosti napĂĄjecĂ­ho napětĂ­ směrem k prahovĂ©mu napětĂ­ u tranzistorĆŻ MOS (MOST). V prĂĄci jsou podrobně pƙedstaveny nejdĆŻleĆŸitějĆĄĂ­ charakteristiky nekonvenčnĂ­ch technik CMOS. Tyto techniky byly pouĆŸity pro vytvoƙenĂ­ nĂ­zko napěƄovĂœch a nĂ­zko vĂœkonovĂœch CMOS struktur u některĂœch aktivnĂ­ch prvkĆŻ, napƙ. Operational Transconductance Amplifier (OTA) zaloĆŸenĂ© na BD, FG, QFG, a BD-QFG techniky; Tunable Transconductor zaloĆŸenĂœ na BD MOST; Current Conveyor Transconductance Amplifier (CCTA) zaloĆŸenĂœ na BD-QFG MOST; Z Copy-Current Controlled-Current Differencing Buffered Amplifier (ZC-CC-CDBA) zaloĆŸenĂœ na BD MOST; Winner Take All (WTA) and Loser Take All (LTA) zaloĆŸenĂœ na BD MOST; Fully Balanced Four-Terminal Floating Nullor (FBFTFN) zaloĆŸenĂœ na BD-QFG technice. Za Ășčelem ověƙenĂ­ funkčnosti vĂœĆĄe zmĂ­něnĂœch struktur, byly tyto struktury pouĆŸity v několika aplikacĂ­ch. VĂœkon navrĆŸenĂœch aktivnĂ­ch prvkĆŻ a pƙíkladech aplikacĂ­ je ověƙovĂĄn prostƙednictvĂ­m simulačnĂ­ch programĆŻ PSpice či Cadence za pouĆŸitĂ­ technologie 0.18 m CMOS.This doctoral thesis deals with designing ultra-low-voltage (LV) low-power (LP) analog circuits utilizing the unconventional CMOS techniques. Battery powered medical devices such as; long term physiological monitoring, portable, implantable, and wearable systems need to be small and lightweight. Besides, long life battery is essential need for these devices. Thus, low-power integrated circuits are always paramount in such biomedical applications. Recently, unconventional CMOS techniques i.e. Bulk-Driven (BD), Floating-Gate (FG), Quasi-Floating-Gate (QFG), Bulk-Driven Floating-Gate (BD-FG) and Bulk-Driven Quasi-Floating-Gate (BD-QFG) MOS transistors (MOSTs) have revealed as effective devices to reduce the circuit complexity and push the voltage supply of the circuit towards threshold voltage of the MOST. In this work, the most important features of the unconventional CMOS techniques are discussed in details. These techniques have been utilized to perform ultra-LV LP CMOS structures of several active elements i.e. Operational Transconductance Amplifier (OTA) based on BD, FG, QFG, and BD-QFG techniques; Tunable Transconductor based on BD MOST; Current Conveyor Transconductance Amplifier (CCTA) based on BD-QFG MOST; Z Copy-Current Controlled-Current Differencing Buffered Amplifier (ZC-CC-CDBA) based on BD MOST; Winner Take All (WTA) and Loser Take All (LTA) based on BD MOST; Fully Balanced Four-Terminal Floating Nullor (FBFTFN) based on BD-QFG technique. Moreover, to verify the workability of the proposed structures, they were employed in several applications. The performance of the proposed active elements and their applications were investigated through PSpice or Cadence simulation program using 0.18 m CMOS technology.

    Low-Noise Micro-Power Amplifiers for Biosignal Acquisition

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    There are many different types of biopotential signals, such as action potentials (APs), local field potentials (LFPs), electromyography (EMG), electrocardiogram (ECG), electroencephalogram (EEG), etc. Nerve action potentials play an important role for the analysis of human cognition, such as perception, memory, language, emotions, and motor control. EMGs provide vital information about the patients which allow clinicians to diagnose and treat many neuromuscular diseases, which could result in muscle paralysis, motor problems, etc. EEGs is critical in diagnosing epilepsy, sleep disorders, as well as brain tumors. Biopotential signals are very weak, which requires the biopotential amplifier to exhibit low input-referred noise. For example, EEGs have amplitudes from 1 ÎŒV [microvolt] to 100 ÎŒV [microvolt] with much of the energy in the sub-Hz [hertz] to 100 Hz [hertz] band. APs have amplitudes up to 500 ÎŒV [microvolt] with much of the energy in the 100 Hz [hertz] to 7 kHz [hertz] band. In wearable/implantable systems, the low-power operation of the biopotential amplifier is critical to avoid thermal damage to surrounding tissues, preserve long battery life, and enable wirelessly-delivered or harvested energy supply. For an ideal thermal-noise-limited amplifier, the amplifier power is inversely proportional to the input-referred noise of the amplifier. Therefore, there is a noise-power trade-off which must be well-balanced by the designers. In this work I propose novel amplifier topologies, which are able to significantly improve the noise-power efficiency by increasing the effective transconductance at a given current. In order to reject the DC offsets generated at the tissue-electrode interface, energy-efficient techniques are employed to create a low-frequency high-pass cutoff. The noise contribution of the high-pass cutoff circuitry is minimized by using power-efficient configurations, and optimizing the biasing and dimension of the devices. Sufficient common-mode rejection ratio (CMRR) and power supply rejection ratio (PSRR) are achieved to suppress common-mode interferences and power supply noises. Our design are fabricated in standard CMOS processes. The amplifiers’ performance are measured on the bench, and also demonstrated with biopotential recordings

    Circuits for Analog Signal Processing Employing Unconventional Active Elements

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    DisertačnĂ­ prĂĄce se zabĂœvĂĄ zavĂĄděnĂ­m novĂœch struktur modernĂ­ch aktivnĂ­ch prvkĆŻ pracujĂ­cĂ­ch v napěƄovĂ©m, proudovĂ©m a smĂ­ĆĄenĂ©m reĆŸimu. Funkčnost a chovĂĄnĂ­ těchto prvkĆŻ byly ověƙeny prostƙednictvĂ­m SPICE simulacĂ­. V tĂ©to prĂĄci je zahrnuta ƙada simulacĂ­, kterĂ© dokazujĂ­ pƙesnost a dobrĂ© vlastnosti těchto prvkĆŻ, pƙičemĆŸ velkĂœ dĆŻraz byl kladen na to, aby tyto prvky byly schopny pracovat pƙi nĂ­zkĂ©m napĂĄjecĂ­m napětĂ­, jelikoĆŸ poptĂĄvka po pƙenosnĂœch elektronickĂœch zaƙízenĂ­ch a implantabilnĂ­ch zdravotnickĂœch pƙístrojĂ­ch stĂĄle roste. Tyto pƙístroje jsou napĂĄjeny bateriemi a k tomu, aby byla prodlouĆŸena jejich ĆŸivotnost, trend navrhovĂĄnĂ­ analogovĂœch obvodĆŻ směƙuje k stĂĄle větĆĄĂ­mu sniĆŸovĂĄnĂ­ spotƙeby a napĂĄjecĂ­ho napětĂ­. HlavnĂ­m pƙínosem tĂ©to prĂĄce je nĂĄvrh novĂœch CMOS struktur: CCII (Current Conveyor Second Generation) na zĂĄkladě BD (Bulk Driven), FG (Floating Gate) a QFG (Quasi Floating Gate); DVCC (Differential Voltage Current Conveyor) na zĂĄkladě FG, transkonduktor na zĂĄkladě novĂ© techniky BD_QFG (Bulk Driven_Quasi Floating Gate), CCCDBA (Current Controlled Current Differencing Buffered Amplifier) na zĂĄkladě GD (Gate Driven), VDBA (Voltage Differencing Buffered Amplifier) na zĂĄkladě GD a DBeTA (Differential_Input Buffered and External Transconductance Amplifier) na zĂĄkladě BD. DĂĄle je uvedeno několik zajĂ­mavĂœch aplikacĂ­ uĆŸĂ­vajĂ­cĂ­ch vĂœĆĄe jmenovanĂ© prvky. ZĂ­skanĂ© vĂœsledky simulacĂ­ odpovĂ­dajĂ­ teoretickĂœm pƙedpokladĆŻm.The dissertation thesis deals with implementing new structures of modern active elements working in voltage_, current_, and mixed mode. The functionality and behavior of these elements have been verified by SPICE simulation. Sufficient numbers of simulated plots are included in this thesis to illustrate the precise and strong behavior of those elements. However, a big attention to implement active elements by utilizing LV LP (Low Voltage Low Power) techniques is given in this thesis. This attention came from the fact that growing demand of portable electronic equipments and implantable medical devices are pushing the development towards LV LP integrated circuits because of their influence on batteries lifetime. More specifically, the main contribution of this thesis is to implement new CMOS structures of: CCII (Current Conveyor Second Generation) based on BD (Bulk Driven), FG (Floating Gate) and QFG (Quasi Floating Gate); DVCC (Differential Voltage Current Conveyor) based on FG; Transconductor based on new technique of BD_QFG (Bulk Driven_Quasi Floating Gate); CCCDBA (Current Controlled Current Differencing Buffered Amplifier) based on conventional GD (Gate Driven); VDBA (Voltage Differencing Buffered Amplifier) based on GD. Moreover, defining new active element i.e. DBeTA (Differential_Input Buffered and External Transconductance Amplifier) based on BD is also one of the main contributions of this thesis. To confirm the workability and attractive properties of the proposed circuits many applications were exhibited. The given results agree well with the theoretical anticipation.

    Low-voltage Low-power Bulk-driven CMOS Op-Amp Using Negative Miller Compensation for ECG

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    Two bulk-driven CMOS (Complementary Metal Oxide Semiconductor) operational amplifier (op-amp) designs for electrocardiogram (ECG) application are presented and compared in this paper. Both op-amps are based on two-stage amplification, where bulk-driven differential input is the first stage, while additional DC gain is the second stage. Different compensation techniques were integrated in each op-amp design. Standard Miller compensation was used for the first op-amp parallel with the second stage. The novelty of the second op-amp is that it utilizes negative Miller compensation between the bulk-driven input node and the output node of the first stag, while standard Miller compensation was used in the second stage. The purpose of this work was to compare DC gain, phase margin (PM) and unit gain frequency (UGF) obtained through different simulated compensation strategies and test results. The op-amps were simulated using 0.25 ÎŒm CMOS technology. The simulation results are presented using the standard model libraries from Tanner EDA tools, operating on a single rail +0.8V power supply

    Low-voltage Low-power Bulk-driven CMOS Op-Amp Using Negative Miller Compensation for ECG

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    Two bulk-driven CMOS (Complementary Metal Oxide Semiconductor) operational amplifier (op-amp) designs for electrocardiogram (ECG) application are presented and compared in this paper. Both op-amps are based on two-stage amplification, where bulk-driven differential input is the first stage, while additional DC gain is the second stage. Different compensation techniques were integrated in each op-amp design. Standard Miller compensation was used for the first op-amp parallel with the second stage. The novelty of the second op-amp is that it utilizes negative Miller compensation between the bulk-driven input node and the output node of the first stag, while standard Miller compensation was used in the second stage. The purpose of this work was to compare DC gain, phase margin (PM) and unit gain frequency (UGF) obtained through different simulated compensation strategies and test results. The op-amps were simulated using 0.25 ÎŒm CMOS technology. The simulation results are presented using the standard model libraries from Tanner EDA tools, operating on a single rail +0.8V power supply

    Performance enhancement in the desing of amplifier and amplifier-less circuits in modern CMOS technologies.

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    In the context of nowadays CMOS technology downscaling and the increasing demand of high performance electronics by industry and consumers, analog design has become a major challenge. On the one hand, beyond others, amplifiers have traditionally been a key cell for many analog systems whose overall performance strongly depends on those of the amplifier. Consequently, still today, achieving high performance amplifiers is essential. On the other hand, due to the increasing difficulty in achieving high performance amplifiers in downscaled modern technologies, a different research line that replaces the amplifier by other more easily achievable cells appears: the so called amplifier-less techniques. This thesis explores and contributes to both philosophies. Specifically, a lowvoltage differential input pair is proposed, with which three multistage amplifiers in the state of art are designed, analysed and tested. Moreover, a structure for the implementation of differential switched capacitor circuits, specially suitable for comparator-based circuits, that features lower distortion and less noise than the classical differential structures is proposed, an, as a proof of concept, implemented in a ΔΣ modulator
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