40 research outputs found

    Realization of Resistorless Lossless Positive and Negative Grounded Inductor Simulators Using Single ZC-CCCITA

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    This paper is in continuation with the very recent work of Prasad et al. [14], wherein new realizations of grounded and floating positive inductor simulator using current differencing transconductance amplifier (CDTA) are reported. The focus of the paper is to provide alternate realizations of lossless, both positive and negative inductor simulators (PIS and NIS) in grounded form using z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), which can be considered as a derivative of CDTA, wherein the current differencing unit (CDU) is reduced to a current-controlled current inverting unit. We demonstrate that only a single ZC-CCCITA and one grounded capacitor are sufficient to realize grounded lossless PIS or NIS. The proposed circuits are resistorless whose parameters can be controlled through the bias currents. The workability of the proposed PIS is validated by SPICE simulations on three RLC prototypes

    Electronically-Controllable Floating Inductor using OMA with Enhanced Input Dynamic Range

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    Abstract Recently a new formulation for realizing a floating inductance (FI) using an OMA, which takes into account the dominant pole of the op-amp employed in the OMA, without requiring any external capacitor was proposed. The proposition, however, suffered from a limited inputdynamic-range of operation owing to limited open-loop signal handling capability of the op-amp used. In this paper we propose an improved FI formulation with increased input signal handling capability. The electronically controllable floating inductance feature of the resulting circuit has been shown by replacing all the building blocks of the FI formulation by their CMOS counterparts. The workability of the proposed FI has been demonstrated by PSPICE simulations

    Realization of New Electronically Controllable Grounded and Floating Simulated Inductance Circuits Using Voltage Differencing Differential Input Buffered Amplifiers

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    A new active circuit is proposed for the realisation of lossless grounded and floating inductance employing Voltage Differencing Differential Input Buffered Amplifiers (VD-DIBAs). The proposed grounded simulated inductance circuit employs two VD-DIBAs and a single-grounded capacitor whereas the floating simulated inductance circuit employs three VD-DIBAs and a grounded capacitor. The circuit for grounded inductance does not require any realization conditions whereas in case of floating inductance, only equality of two transconductances is needed. Some sample results demonstrating the applications of the new simulated inductors using VD-DIBAs have been given to confirm the workability of the new circuits

    Fully-Differential Frequency Filters with Modern Active Elements

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    Tato disertačnĂ­ prĂĄce se zaměƙuje na vĂœzkum v oblasti frekvenčnĂ­ch filtrĆŻ. HlavnĂ­m cĂ­lem je navrhnout a analyzovat plně diferenčnĂ­ kmitočtovĂ© filtry pracujĂ­cĂ­ v proudovĂ©m mĂłdu a vyuĆŸĂ­vajĂ­cĂ­ modernĂ­ aktivnĂ­ prvky. PrezentovanĂ© filtry jsou navrĆŸeny za pouĆŸitĂ­ proudovĂœch sledovačƯ, operačnĂ­ch transkonduktančnĂ­ch zesilovačƯ, plně diferenčnĂ­ch proudovĂœch zesilovačƯ a transrezistančnĂ­ch zesilovačƯ. NĂĄvrh se zaměƙuje na moĆŸnost ƙídit některĂœ z typickĂœch parametrĆŻ filtru pomocĂ­ ƙiditelnĂœch aktivnĂ­ch prvkĆŻ, kterĂ© jsou vhodně umĂ­stněny do obvodovĂ© struktury. JednotlivĂ© prezentovanĂ© filtry jsou navrĆŸeny v nediferenčnĂ­ a diferenčnĂ­ verzi. VelkĂœ dĆŻraz je věnovĂĄn srovnĂĄnĂ­ plně diferenčnĂ­ch struktur s jejich odpovĂ­dajĂ­cĂ­mi nediferenčnĂ­mi formami. Funkčnost jednotlivĂœch nĂĄvrhĆŻ je ověƙena simulacemi a v některĂœch pƙípadech i experimentĂĄlnĂ­m měƙenĂ­m.This doctoral thesis focuses on research in the field of frequency filters. The main goal is to propose and analyze fully-differential current-mode frequency filters employing modern active elements. Presented filters are proposed using current followers, operational transconductance amplifiers, digitally adjustable current amplifiers and transresistance amplifiers. The proposal is focusing on ability to control some of the typical filter parameter or parameters using controllable active elements suitably placed in the circuit structure. Individual presented filters are proposed in their single-ended and fully-differential forms. Great emphasis is paid to a comparison of the fully-differential structures and their corresponding single-ended forms. The functionality of each proposal is verified by simulations and in some cases also by experimental measurements.

    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 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.

    Modeling and design of an active silicon cochlea

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references.Silicon cochleas are inspired by the biological cochlea and perform efficient spectrum analysis: They realize a bank of constant-Q Nth-order filters with O(N) efficiency rather than O(NÂČ) efficiency due to their use of an exponentially tapered filter cascade. They are useful in speech-recognition front ends, cochlear implants, and hearing aids, especially as architectures for improving spectral analysis in noisy environments and for performing low-power spectrum analysis. In this thesis I describe four contributions towards improving the state-of-the-art in silicon-cochlea design, two of which involve theoretical modeling, and two of which involve integrated-circuit design. On the theoretical side, I first show that a simple rational approximation to distributed partition impedances in the biological cochlea captures its essential features and enables an efficient artificial implementation achieving maximum gain in a minimum number of stages while still maintaining stability. In particular, I show that the terminating impedance of the cochlea is crucial for its stability and discuss various analytic methods for termination. Second, I derive a novel composite artificial cochlear architecture composed of a cascade of all-pass second-order filters from a first-principles analysis of the biological cochlear transmission line. The novel all-pass architecture reduces phase lag and group delay in the silicon cochlea, a problem in prior designs, sharpens its high-frequency rolloff slopes, increases its frequency selectivity, and improves its nonlinear compression characteristics. On the circuit side, I first present a novel current-mode log-domain topology that simultaneously increases signal-to-noise ratio (SNR) and dynamic range while lowering power consumption in resonant filters with high quality factor Q.(cont.) The novel topology is validated in a second-order low-pass resonant filter, which is employed in the silicon cochlea, demonstrating a reduction in power consumption and increase in SNR by a factor of Q. When bias currents in the filter are adjusted as the signal level varies, this technique enables an improvement in maximum SNR by a factor of Q and an increase in maximum non-distorted signal power and dynamic range by a factor of Q⁎. Measurements from a chip in a 0.18-[mu]m 1.1-V CMOS technology achieve a quiescent power consumption of 580-nW at a 15-kHz center frequency with a maximum SNR of 41.3dB and dynamic range of 76dB for a Q=4. Finally, I describe a current-mode -stage 0.18-[mu]m silicon cochlea that achieves 79dB of dynamic range with 41-[mu]W power consumption on a 1-V power supply over a usable 3.5kHz-14kHz frequency range. These numbers represent an 18dB improvement in dynamic range and a 12.5x reduction in power consumption over prior state-of-the-art silicon cochleas.by Serhii M. Zhak.Ph.D

    Wireless power transmission utilizing a phased array of Tesla coils

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 245-247).This thesis discusses the theory and design of coupled resonant systems and how they can be linked in a phased array for the wireless transmission of electrical power. A detailed derivation of their operational theory is presented with a strong emphasis on the current and voltage waveforms produced. Formulas are presented relating the features of the waveforms to specific parameters of the system. They provide a theoretical basis for the design of the TeslaE coil systems. Unloaded and loaded operating efficiency is considered from both a power and energy perspective with emphasis on maximizing the two quantities. With these design formulas, a working set of two distinct coupled resonant systems were locked in frequency and controllable in phase to produce a phased array capable of wireless power transmission. The operational details and practical design considerations are presented and explained. The measured output waveforms were found to closely agree with the predicted models.by Joseph C. Stark, III.M.Eng

    Palmo : a novel pulsed based signal processing technique for programmable mixed-signal VLSI

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    In this thesis a new signal processing technique is presented. This technique exploits the use of pulses as the signalling mechanism. This Palmo 1 signalling method applied to signal processing is novel, combining the advantages of both digital and analogue techniques. Pulsed signals are robust, inherently low-power, easily regenerated, and easily distributed across and between chips. The Palmo cells used to perform analogue operations on the pulsed signals are compact, fast, simple and programmable
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