Design of the fully differential operational floating conveyor and its applications

Analog circuits can be generally classified into two broad categories: The first one includes analog circuits operating in the voltage mode, while the second category includes those operating in the current mode. Voltage mode analog circuit’s bandwidth is highly dependent on the gain via the gain bandwidth product (GBP). To solve this problem, many current mode circuits are developed such as the second generation Current Conveyor (CCII) and the Operational Floating Conveyor (OFC). A novel concept of the Fully Differential Operational Floating Conveyor (FD-OFC) is presented for the first time, to the best of the author’s knowledge. A CMOS design for the proposed FD-OFC is introduced as an 8 (4x4) port general purpose analog building block. The FD-OFC design is implemented using two different realizations. The proposed design has the advantage of low power consumption as it operates under biasing conditions of only 1.2 V while its wide bandwidth reaches 600 MHz. These operating conditions recommend the proposed device to be integrated to a wide range of low power-wide high speed applications. The terminal behavior of the proposed device is mathematically modeled and its operation is simulated using the UMC 130 nm technology kit in Cadence environment. Differential voltage amplifier, current mode instrumentation amplifier (CMIA) and Fully Differential second generation Current Conveyor (FDCCII) are examples of the presented applications based on the proposed FD-OFC

Novel active function blocks and their applications in frequency filters and quadrature oscillators

Kmitočtové filtry a sinusoidní oscilátory jsou lineární elektronické obvody, které jsou používány v široké oblasti elektroniky a jsou základními stavebními bloky v analogovém zpracování signálu. V poslední dekádě pro tento účel bylo prezentováno velké množství stavebních funkčních bloků. V letech 2000 a 2006 na Ústavu telekomunikací, VUT v Brně byly definovány univerzální proudový konvejor (UCC) a univerzální napět'ový konvejor (UVC) a vyrobeny ve spolupráci s firmou AMI Semiconductor Czech, Ltd. Ovšem, stále existuje požadavek na vývoj nových aktivních prvků, které nabízejí nové výhody. Hlavní přínos práce proto spočívá v definici dalších původních aktivních stavebních bloků jako jsou differential-input buffered and transconductance amplifier (DBTA), current follower transconductance amplifier (CFTA), z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), generalized current follower differential input transconductance amplifier (GCFDITA), voltage gain-controlled modified current-feedback operational amplifier (VGC-MCFOA), a minus-type current-controlled third-generation voltage conveyor (CC-VCIII-). Pomocí navržených aktivních stavebních bloků byly prezentovány původní zapojení fázovacích článků prvního řádu, univerzální filtry druhého řádu, ekvivalenty obvodu typu KHN, inverzní filtry, aktivní simulátory uzemněného induktoru a kvadraturní sinusoidní oscilátory pracující v proudovém, napět'ovém a smíšeném módu. Chování navržených obvodů byla ověřena simulací v prostředí SPICE a ve vybraných případech experimentálním měřením.Frequency filters and sinusoidal oscillators are linear electric circuits that are used in wide area of electronics and also are the basic building blocks in analogue signal processing. In the last decade, huge number of active building blocks (ABBs) were presented for this purpose. In 2000 and 2006, the universal current conveyor (UCC) and the universal voltage conveyor (UVC), respectively, were designed at the Department of Telecommunication, BUT, Brno, and produced in cooperation with AMI Semiconductor Czech, Ltd. There is still the need to develop new active elements that offer new advantages. The main contribution of this thesis is, therefore, the definition of other novel ABBs such as the differential-input buffered and transconductance amplifier (DBTA), the current follower transconductance amplifier (CFTA), the z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), the generalized current follower differential input transconductance amplifier (GCFDITA), the voltage gain-controlled modified current-feedback operational amplifier (VGC-MCFOA), and the minus-type current-controlled third-generation voltage conveyor (CC-VCIII-). Using the proposed ABBs, novel structures of first-order all-pass filters, second-order universal filters, KHN-equivalent circuits, inverse filters, active grounded inductance simulators, and quadrature sinusoidal oscillators working in the current-, voltage-, or mixed-mode are presented. The behavior of the proposed circuits has been verified by SPICE simulations and in selected cases also by experimental measurements.

An electrocardiogram readout circuit based on CMOS operational floating current conveyor

Electrocardiogram (ECG) is used in diagnosing heart diseases. It is designed as integration between current-mode instrumentation amplifiers (CMIA) and low pass filter (LPF). Normal heart behavior can be identified simply by normal ECG that consists of signal while heart disorder can be recognized by having differences in the features of their corresponding ECG waveform. A novel integrated CMOS-based operational floating current conveyor (OFCC) circuit is proposed. OFCC is a five port general purpose analog building block which combines all the features of different current mode devices such as the second generation current conveyor (CCII), the current feedback operational amplifier (CFA), and the operational floating conveyor (OFC). The OFFC is modeled and simulated using UMC 130nm CMOS technology kit in Cadence with a supply voltage 1.2V. The ECG readout circuit has been designed using the proposed OFCC as a building block. The advantages of this: it is integrated, noise factor is small as the proposed OFCC has the lowest input noise voltage and the layout is simple as it is a single block that can be repeated several times

A New Proposal for OFCC-based Instrumentation Amplifier

This contribution puts forward a new voltage mode instrumentation amplifier (VMIA) based on operational floating current conveyor (OFCC). It presents high impedance at input terminals and provides output at low impedance making the proposal ideal for voltage mode operation. The proposed VMIA architecture has two stages - the first stage comprises of two OFCCs to sense input voltages and coverts the voltage difference to current while the second stage has single OFCC that converts the current to voltage. In addition it employs two resistors to provide gain and imposes no condition on the values of resistors.  The behavior of the proposed structure is also analyzed for OFCC non idealities namely finite transimpedance and tracking error. The proposal is verified through SPICE simulations using CMOS based schematic of OFCC. Experimental results, by bread boarding it using commercially available IC AD844, are also included

Realization of OFCC based transimpedance mode instrumentation amplifier

The paper presents an instrumentation amplifier suitable for amplifying the current source transducer signals. It provides a voltage output. It has a high gain, common mode rejection ratio and gain independent bandwidth. It uses three Operational Floating Current Conveyors (OFCCs) and four resistors. The effect of nonidealities of OFCC on performance of proposed transimpedance instrumentation amplifier (TIA) is also analyzed. The proposal has been verified through SPICE simulations using CMOS based schematicThe paper presents an instrumentation amplifier suitable for amplifying the current source transducer signals. It provides a voltage output. It has a high gain, common mode rejection ratio and gain independent bandwidth. It uses three operational floating current conveyors (OFCCs) and four resistors. The effect of nonidealities of OFCC on performance of proposed transimpedance instrumentation amplifier (TIA) is also analyzed. The proposal has been verified through SPICE simulations using CMOS based schematic

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

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

Low-Voltage Ultra-Low-Power Current Conveyor Based on Quasi-Floating Gate Transistors

The field of low-voltage low-power CMOS technology has grown rapidly in recent years; it is an essential prerequisite particularly for portable electronic equipment and implantable medical devices due to its influence on battery lifetime. Recently, significant improvements in implementing circuits working in the low-voltage low-power area have been achieved, but circuit designers face severe challenges when trying to improve or even maintain the circuit performance with reduced supply voltage. In this paper, a low-voltage ultra-low-power current conveyor second generation CCII based on quasi-floating gate transistors is presented. The proposed circuit operates at a very low supply voltage of only ±0.4 V with rail-to-rail voltage swing capability and a total quiescent power consumption of mere 9.5 µW. Further, the proposed circuit is not only able to process the AC signal as it's usual at quasi-floating gate transistors but also the DC which extends the applicability of the proposed circuit. In conclusion, an application example of the current-mode quadrature oscillator is presented. PSpice simulation results using the 0.18 µm TSMC CMOS technology are included to confirm the attractive properties of the proposed circuit

A Modified Bipolar Translinear Cell with Improved Linear Range and Its Applications

This paper presents a technique to extend the linear input voltage range of a sinh mixed translinear cell proposed by Fabre [1]. This technique extends the linear operation range of the circuit by inserting common-anode-connected pairs into the mixed translinear cell. Then the relationship between the output current and the input voltage is developed to be linear. The transconductance gain can be adjusted electronically while keeping its linearity. The performance of the proposed circuit is verified by mathematical analysis and by SPICE simulations. Finally, applications of the proposed cell in a floating resistor and a CCCII for designing an instrumentation amplifier are presented

Study of Adjustable Gains for Control of Oscillation Frequency and Oscillation Condition in 3R-2C Oscillator

An idea of adjustable gain in order to obtain controllable features is very useful for design of tuneable oscillators. Several active elements with adjustable properties (current and voltage gain) are discussed in this paper. Three modified oscillator conceptions that are quite simple, directly electronically adjustable, providing independent control of oscillation condition and frequency were designed. Positive and negative aspects of presented method of control are discussed. Expected assumptions of adjustability are verified experimentally on one of the presented solution

Current and Voltage Mode Multiphase Sinusoidal Oscillators Using CBTAs

Current-mode (CM) and voltage-mode (VM) multiphase sinusoidal oscillator (MSO) structures using current backward transconductance amplifier (CBTA) are proposed. The proposed oscillators can generate n current or voltage signals (n being even or odd) equally spaced in phase. n+1 CBTAs, n grounded capacitors and a grounded resistor are used for nth-state oscillator. The oscillation frequency can be independently controlled through transconductance (gm) of the CBTAs which are adjustable via their bias currents. The effects caused by the non-ideality of the CBTA on the oscillation frequency and condition have been analyzed. The performance of the proposed circuits is demonstrated on third-stage and fifth-stage MSOs by using PSPICE simulations based on the 0.25 µm TSMC level-7 CMOS technology parameters