High Input Impedance Voltage-Mode Biquad Filter Using VD-DIBAs

This paper deals with a single-input multiple-output biquadratic filter providing three functions (low-pass, high-pass and band-pass) based on voltage differencing differential input buffered amplifier (VD-DIBA). The quality factor and pole frequency can be electronically tuned via the bias current. The proposed circuit uses two VD-DIBAs and two grounded capacitors without any external resistors, which is suitable to further develop into an integrated circuit. Moreover, the circuit possesses high input impedance, providing easy voltage-mode cascading. It is shown that the filter structure can be easily extended to multi-input filter without any additional components, providing also all-pass and band-reject properties. The PSPICE simulation and experimental results are included, verifying the key characteristics of the proposed filter. The given results agree well with the theoretical presumptions

Current-Controlled Current-Mode Universal Biquad Employing Multi-Output Transconductors

This paper deals with RC active biquad working in the so-called current mode (CM). The design approach uses only three transconductors (OTA) with the minimum necessary number of outputs and with only three passive grounded elements. The proposed filter has simple circuit configuration providing all standard transfer functions such as high-pass (HP), band-pass (BP), low-pass (LP), band-reject (BR) and all-pass (AP). Electronic tuning and independent adjusting of the quality factor and bandwidth of BP filter is possible. The presented circuits are verified by PSpice simulations utilizing OTAs on transistor level of abstraction. The linear parasitic effects of the real active elements in each suggested circuit are briefly discussed. Experimental verification is also given. Designed networks can be used in many applications such as antialiasing filters, in high-speed data telecommunication systems, for signal processing in the cable modems, in regulation and measurement techniques etc

New CMOS Realization of Voltage Differencing Buffered Amplifier and Its Biquad Filter Applications

In this paper, new biquad filter configuration using a recently introduced active element, namely Voltage Differencing Buffered Amplifier (VDBA), is proposed. This block has high impedance input terminals and low impedance output terminal, providing advantages at voltage mode circuits. Besides, VDBA has a transconductance gain, thus the proposed circuits can be employed without using any external resistors. Two new voltage-mode biquad filter configurations are presented for VDBA application. Each proposed filter employs two active elements and two or three passive components. Filters, having three inputs and single output, can realize voltage-mode low-pass, band-pass, high-pass, band-stop, and all-pass filters. The biquad filters have low output impedances that is necessity for cascadability for voltage mode circuits, and no critical component matching conditions are required. For the second biquad, quality factor can be adjusted via resistor independently of the natural frequency. Simulation results are given to, confirming the theoretical analysis. The proposed biquad filters are simulated using TSMC CMOS 0.35 µm technology. LTSPICE simulations of the proposed circuits give results that agree well with the theoretical analysis

Voltage-Mode Multifunction Biquadratic Filters Using New Ultra-Low-Power Differential Difference Current Conveyors

This paper presents two low-power voltage-mode multifunction biquadratic filters using differential difference current conveyors. Each proposed circuit employs three differential difference current conveyors, two grounded capacitors and two grounded resistors. The low-voltage ultra-low-power differential difference current conveyor is used to provide low-power consumption of the proposed filters. By appropriately connecting the input and output terminals, the proposed filters can provide low-pass, band-pass, high-pass, band-stop and all-pass voltage responses at high-input terminals, which is a desirable feature for voltage-mode operations. The natural frequency and the quality factor can be orthogonally set by adjusting the circuit components. For realizing all the filter responses, no inverting-type input signal requirements as well as no component-matching conditional requirements are imposed. The incremental parameter sensitivities are also low. The characteristics of the proposed circuits are simulated by using PSPICE simulators to confirm the presented theory

Low Voltage Low Power Analogue Circuits Design

Disertační práce je zaměřena na výzkum nejběžnějších metod, které se využívají při návrhu analogových obvodů s využití nízkonapěťových (LV) a nízkopříkonových (LP) struktur. Tyto LV LP obvody mohou být vytvořeny díky vyspělým technologiím nebo také využitím pokročilých technik návrhu. Disertační práce se zabývá právě pokročilými technikami návrhu, především pak nekonvenčními. Mezi tyto techniky patří využití prvků s řízeným substrátem (bulk-driven - BD), s plovoucím hradlem (floating-gate - FG), s kvazi plovoucím hradlem (quasi-floating-gate - QFG), s řízeným substrátem s plovoucím hradlem (bulk-driven floating-gate - BD-FG) a s řízeným substrátem s kvazi plovoucím hradlem (quasi-floating-gate - BD-QFG). Práce je také orientována na možné způsoby implementace známých a moderních aktivních prvků pracujících v napěťovém, proudovém nebo mix-módu. 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 účelem potvrzení funkčnosti a chování výše zmíněných struktur a prvků byly vytvořeny příklady aplikací, které simulují usměrňovací a induktanční vlastnosti diody, dále pak filtry dolní propusti, pásmové propusti a také univerzální filtry. Všechny aktivní prvky a příklady aplikací byly ověřeny pomocí PSpice simulací s využitím parametrů technologie 0,18 m TSMC CMOS. Pro ilustraci přesného a účinného chování struktur je v disertační práci zahrnuto velké množství simulačních výsledků.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.

Single-Input Five-Output Electronically Tunable Current-Mode Biquad Consisting of Only ZC-CFTAs and Grounded Capacitors

This paper presents an electronically tunable current-mode biquadratic filter constructing with four Z-copy current follower transconductance amplifiers (ZC-CFTAs) and only two grounded capacitors. The presented filter can realize all the five standard biquadratic functions simultaneously without requiring any component matching conditions and connecting any relevant output currents. The circuit has one low-impedance input and five high-impedance outputs, resulting in easy cascadability in current-mode. Also, the developed circuit exhibits the advantage of non-interactive electronic control of the natural angular frequency and the quality factor Q along with low incremental active and passive sensitivities. Computer simulation results using PSPICE program are given to confirm the validity of the theoretical prediction and to point out the attractive performance of the circuit

A New Current Mode SIMO-Type Universal Biquad Employing Multi-Output Current Conveyors (MOCCIIs)

This study presents a new current-mode singleinput and multi-output (SIMO) type universal biquad circuit using second generation multi-output current conveyors (MOCCII) as the active components. The proposed circuit employs three MOCCIIs, two grounded capacitors and four grounded resistors, therefore offers electroning tuning possibilities. It can simultaneously realize second order low-pass, band-pass, high-pass, notch and all-pass filters. The circuit is cascadable and has low sensitivities. It provides independent control of ω0 (natural angular frequency) and Q (quality factor). The influences of MOCCII parasitic elements have been analyzed and simulated using PSPICE. Experimental results including frequency responses of low-pass, high-pass, band-pass and band-stop filters, as well as frequency responses of filters with different ω0 (keeping Q invariable) and different Q (keeping ω0 invariable) are shown to be in agreement with theory

Unconventional Circuit Elements for Ladder Filter Design

Kmitočtové filtry jsou lineární elektrické obvody, které jsou využívány v různých oblastech elektroniky. Současně tvoří základní stavební bloky pro analogové zpracování signálů. V poslední dekádě bylo zavedeno množství aktivních stavebních bloků pro analogové zpracování signálů. Stále však existuje potřeba vývoje nových aktivních součástek, které by poskytovaly nové možnosti a lepší parametry. V práci jsou diskutovány různé aspekty obvodů pracujících v napěťovém, proudovém a smíšném módu. Práce reaguje na dnešní potřebu nízkovýkonových a nízkonapěťových aplikací pro přenosné přístroje a mobilní komunikační systémy a na problémy jejich návrhu. Potřeba těchto výkonných nízkonapěťových zařízení je výzvou návrhářů k hledání nových obvodových topologií a nových nízkonapěťových technik. V práci je popsána řada aktivních prvků, jako například operační transkonduktanční zesilovač (OTA), proudový konvejor II. generace (CCII) a CDTA (Current Differencing Transconductance Amplifier). Dále jsou navrženy nové prvky, jako jsou VDTA (Voltage Differencing Transconductance Amplifier) a VDVTA (Voltage Differencing Voltage Transconductance Amplifier). Všechny tyto prvky byly rovněž implementovány pomocí "bulk-driven" techniky CMOS s cílem realizace nízkonapěťových aplikací. Tato práce je rovněž zaměřena na náhrady klasických induktorů syntetickými induktory v pasivních LC příčkových filtrech. Tyto náhrady pak mohou vést k syntéze aktivních filtrů se zajímavými vlastnostmi.Frequency filters are linear electric circuits that are used in wide area of electronics. They are also the basic building blocks in analogue signal processing. In the last decade, a huge number of active building blocks for analogue signal processing was introduced. However, there is still the need to develop new active elements that offer new possibilities and better parameters. The current-, voltage-, or mixed-mode analog circuits and their various aspects are discussed in the thesis. This work reflects the trend of low-power (LP) low-voltage (LV) circuits for portable electronic and mobile communication systems and the problems of their design. The need for high-performance LV circuits encourages the analog designers to look for new circuit architectures and new LV techniques. This thesis presents various active elements such as Operational Transconductance Amplifier (OTA), Current Conveyor of Second Generation (CCII), and Current Differencing Transconductance Amplifier (CDTA), and introduces novel ones, such as Voltage Differencing Transconductance Amplifier (VDTA) and Voltage Differencing Voltage Transconductance Amplifier (VDVTA). All the above active elements were also designed in CMOS bulk-driven technology for LP LV applications. This thesis is also focused on replacement of conventional inductors by synthetic ones in passive LC ladder filters. These replacements can lead to the synthesis of active filters with interesting parameters.

Electronically Tunable Resistorless Mixed Mode Biquad Filters

This paper presents a new realization of elec¬tronically tunable mixed mode (including transadmittance- and voltage-modes) biquad filter with single input, three outputs or three inputs, single output using voltage differ-encing transconductance amplifier (VDTA), a recently introduced active element. It can simultaneously realize standard filtering signals: low-pass, band-pass and high-pass or by selecting input terminals, it can realize all five different filtering signals: low-pass, band-pass, high-pass, band-stop and all-pass. The proposed filter circuit offers the following attractive feature: no requirement of invert-ing type input signal which is require no addition circuit, critical component matching conditions are not required in the design, the circuit parameters ω0 and Q can be set orthogonally or independently through adjusting the bias currents of the VDTAs, the proposed circuit employs two active and minimum numbers of passive components. Fur-thermore, this filter was investigated from the point of view of limited frequency range, stability conditions, effects of parasitic elements and effects of non-ideal and sensitivity. Thus, taking these effects and conditions into considera¬tion, working conditions and boundaries of this filter are determined. We also performed Monte Carlo, THD and noise analyses. Simulation results are given to confirm theoretical analyses

Tunable Versatile High Input Impedance Voltage-Mode Universal Biquadratic Filter Based on DDCCs

A high input impedance voltage-mode universal biquadratic filter with three input terminals and seven output terminals is presented. The proposed circuit uses three differential difference current conveyors (DDCCs), four resistors and two grounded capacitors. The proposed circuit can realize all the standard filter functions, namely, lowpass, bandpass, highpass, notch and allpass, simultaneously. The proposed circuit offers the features of high input impedance, using only grounded capacitors, and orthogonal controllability of resonance angular frequency and quality factor