Current-controlled Current Differencing Transconductance Amplifier Research Articles

Gain-Controllable Transadmittance-Mode First-Order Allpass Filters with Electronic Tune Using Single Active Element

First-order allpass filters are analog filters with a unit magnitude response, but they change the phase shift between input and output signals at various frequencies. This paper presents the transadmittance-mode first-order allpass filters based on the modified current-controlled current differencing transconductance amplifier (M-CCCDTA). The proposed filters utilize a single M-CCCDTA and a grounded capacitor with no external resistors, making them well suited for implementation in an integrated circuit. The gain and phase response of the proposed filters can be adjusted electronically and separately. Also, the high output impedance of the proposed filters at both the input voltage node and the output current node makes cascading easy without the need for buffer devices. A quadrature sinusoidal oscillator based on the proposed first-order allpass filter has been designed as an example of an application. The PSpice simulation and actual experiments are utilized to validate the functionality of the proposed filters. The simulation and experimental results are consistent with the idea of anticipation.

A Compact Fully Electronically Tunable Memristive Circuit Based on CCCDTA with Experimental Results.

This work presents a flux-controlled memristor structure employing a Current-Controlled Current Differencing Transconductance Amplifier (CCCDTA) with a grounded capacitor. The proposed emulator's invariant and variant parts can be safely adjustable, showing promising characteristics of up to 1.5 MHz operating frequency. Furthermore, there is no need for an additional circuit, switching mechanism or changing the circuit topology for the changing of operation modes. To justify the performance of the emulator with incremental and decremental mode operations, a Monte Carlo and temperature analysis are validated using TSMC 0.18 µm technology under a symmetrical supply voltage of ±0.9 V. Furthermore, the workability of the proposed circuit is tested with commercial elements such as ALD1116, AD844 and LM13700. When compared with other studies, the presented emulator circuit demonstrates promising performance in various features.

An electronically tunable CMOS implementation of capacitance multiplier employing CCCDTA

In this work, a new design for the grounded capacitance multiplier is proposed. The proposed circuit is based on the analog building block of Current Controlled Current Differencing Transconductance Amplifier (CCCDTA) which allows the multiplier structure to work in the current mode. CMOS realization of the proposed structure is implemented with 0.18 µm CMOS technology for the grounded adjustable capacitor multiplier. Multiplication factor adjustability is realized by the bias current of Current Difference Unit (CDU) of CCCDTA. All simulations performed at post-layout level (209 µm × 67 µm) in Cadence environment by taking into account Monte-Carlo runs comprising process variations and transistor mismatches. Also, performance of the proposed multiplier structure is validated by using commercial elements such as AD844 and LM1370. In comparison to the counterparts in the literature, the proposed architecture including only single active element gives promising results under different operating conditions for a wide range of frequency.

Current and Voltage Mode Resistorless Universal Biquad Filter Using a Single CCCDTA

Current mode (CM) Single-input and multi-output (SIMO) and Voltage mode (VM) Multi-input and single-output (MISO) biquad filters are proposed. The presented configurations use one Current controlled current differencing transconductance amplifier (CCCDTA) and two capacitors without any external resistors, which is easy suited for integrated circuit fabrication. The currentmode filter can realize the second-order low pass, band pass, high pass and band stop responses simultaneously. And the voltage-mode filter can realize all the standard filtering functions from the same structure. The natural frequency (ω) and quality factor (Q) of the filters can be controlled electronically by transconductance of the CCCDTA. Moreover, the proposed filters does not require any impedance matching due to its two input resistance can be independently tuned through the diverse external bias currents of CCCDTA. The influences of the CCCDTA non-idealities are also analyzed and both the active and passive sensitivities are considerably low. This design was simulated in PSPICE. Simulation results showed that their performances in power, bandwidth, out-band rejection and in-band ripple are better than the traditional. Additionally, the experiment results are provided in the paper.

Electronically Tunable Inductance Simulator for Monitoring Biomedical Signals

This article presents grounded inductance simulator using single current controlled current differencing transconductance amplifier (CCCDTA) as active element. The simulated inductance value can be controlled electronically by adjusting the bias current of the CCCDTA. The grounded inductance simulator comprises one CCCDTA and one grounded capacitor without any external resistors and component matching requirements. The circuit performances are depicted through PSpice simulations, they show good agreement to theoretical anticipation. An application as second-order low-pass filter is included to confirm the usability of proposed circuit. It is very suitable to realize the proposed filter in monolithic chip to use in biomedical signal processing. Index Terms—CCCDTA, inductance simulator, integrated circuit.

Electronically tunable current-mode biquad filter employing CCCDTAs and grounded capacitors with low input and high output impedance

In this study, a single-input multiple-outputs current-mode analog biquadratic filter, based on current controlled current differencing transconductance amplifier (CCCDTA) is presented. The proposed filter uses two CCCDTAs and two grounded capacitors without any external resistors, which is well suited for integrated circuit implementation. The filter simultaneously gives 3 standard transfer functions, namely, lowpass, highpass and bandpass filters with independent control of quality factor and pole frequency by electronic method. By summing of IHP and LLP, the notch filter can be also achieved. Moreover, the circuit has low input and high output impedance which would be an ideal choice for cascading in current-mode circuit. The PSPICE simulation results are included verifying the workability of the proposed filter. The given results agree well with the theoretical anticipation.

Dual-mode resistorless sinusoidal oscillator using single CCCDTA

This study proposes a new design for a resistorless second-order sinusoidal oscillator. The proposed circuit uses a single current-controlled current-differencing transconductance amplifier (CCCDTA) and two capacitors to perform the functions of a resistorless sinusoidal oscillator. The proposed oscillator provides a voltage output and a current output simultaneously, and can independently control the oscillation condition and oscillation frequency by using the separate bias currents of the CCCDTA. This study first introduces the CCCDTA and the related formulations of the proposed oscillator circuit, and then presents the non-ideal effects, sensitivity analyses, and design considerations of the proposed circuit. The proposed oscillator features a compact topology and dual-mode operation, including low active and passive sensitivities, and has high potential for integration because it is composed of a single CCCDTA and two capacitors. The HSPICE simulation results in this study confirm the feasibility of the new resistorless oscillator circuit.

A Modified Current-Differencing Transconductance Amplifier and Its Applications

This paper presents a new current-mode active element. The idea is based on the Current-Controlled Current-Differencing Transconductance Amplifier (CCCDTA) known from the literature. The modifications introduced to the original CCCDTA circuit made it possible to obtain a component with very wide area of applications. The main parameters of the circuit (resistances, transconductance) can be electrically controlled. Thanks to these features the modified CCCDTA can be used as the basic building block of a continuous time Field Programmable Analog Array (FPAA).

Current-controlled current differencing transconductance amplifier and applications in continuous-time signal processing circuits

This article presents the design for a basic current-mode building block for analogue signal processing, named as Current Controlled Current Differencing Transconductance Amplifier (CCCDTA). Its parasitic resistances at two current input ports can be controlled by an input bias current. As it can be applied in current-mode of all terminals, it is very suitable to use in a current-mode signal processing, which is continually more popular than a voltage one. The proposed element is realized in a bipolar technology and its performance is examined through PSPICE simulations. They display usability of the new active element, where the maximum bandwidth is 65 MHz. The CCCDTA performs low-power consumption and tuning over a wide current range. In addition, some examples as a current-mode universal biquad filter, a current-mode multiplier/divider and floating inductance simulator are included. They occupy only single CCCDTA.

CMOS current-controlled current differencing transconductance amplifier and applications to analog signal processing

This article presents design of a basic current-mode building block for analog signal processing, named as current-controlled current differencing transconductance amplifier (CCCDTA). Its parasitic resistances at two current input ports can be controlled by an input bias current. Owing to working in current-mode of all terminals, it is very suitable to use in a current-mode signal processing, which is continually more popular than a voltage one. The proposed element is realized in a CMOS technology and is examined the performance through PSPICE simulations. They display usability of the new active element, where the maximum bandwidth is 311 MHz. The CMOS CCCDTA performs low power consumption and tuning over a wide current range. In addition, some examples as a current-mode universal biquad filter, floating inductance simulator and quadrature oscillator are included. They occupy only single CCCDTA.

A current-mode analog multiplier/divider based on CCCDTA

A novel simple current-mode analog multiplier/divider, based on current-controlled current-differencing transconductance amplifier (CCCDTA), is presented. The proposed circuit employs only single CCCDTA without any external passive element requirement and it can work as multiplier and divider without changing its topology. In addition, the proposed circuit can work as gain-controllable current amplifier. The circuit performances are depicted through PSPICE simulations. The simulated results show that: for ± 1.5 V power supply, the total harmonic distortion is about 0.1%, the - 3 dB bandwidth is more than 26.94 MHz, maximum input range is about 100 μ A and the output current is low sensitive to temperature variations.