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Two-Quadrant Current-Mode Logarithmic and Anti-logarithmic Amplifiers with Temperature Compensation
(2025-09-01)
Pukkalanun, Tattaya
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Roongmuanpha, Natchanai
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Tangsrirat, Worapong
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Suesut, Taweepol
This paper proposes circuit topologies for realizing two-quadrant current-mode logarithmic and anti logarithmic amplifier configurations with temperature compensation. The design approach employs the translinear approach to generate the output currents that directly correspond to the absolute values of the logarithmic and anti logarithmic functions. The proposed circuits can operate at a low-level supply voltage of 2V with both input and output current signals. A detailed examination of the non-ideal circuit performance has also been considered. To validate their functionality and illustrate their superior thermal stability, the developed circuits have been simulated. All simulations were conducted via PSPICE for a real bipolar transistor model of the HFA3096 technology.
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Cascadable First-Order and Second-Order Inverse Filters Based on Second-Generation Voltage Conveyors
(2025-02-01)
Roongmuanpha, Natchanai
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Likhitkitwoerakul, Nutcha
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Pukkalanun, Tattaya
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Faseehuddin, Mohammad
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Tangsrirat, Worapong
This study introduces four novel configurations of first-order and second-order multifunction inverse filters in both voltage-mode (VM) and current-mode (CM) using second-generation voltage conveyors (VCIIs). The first-order VM and CM inverse filters utilize only three passive components together with one VCII for VM and two VCIIs for CM realizations, which can provide lowpass and highpass inverse filter responses. The latter, second-order VM and CM multifunction inverse filters, can be constructed using the corresponding first-order inverse filters as their core circuits. These filters offer all the basic inverse filter functions, including lowpass, bandpass, and highpass inverse responses with all gains obtained from the same design. All the inverse filter realizations are cascadable. No component matching requirements are necessary for all filter responses. The non-ideal effects of the VCII on the performance of the proposed inverse filters are thoroughly examined. To prove the feasibility of the designs, the PSPICE program performed several simulations, utilizing model parameters of 0.18 µm CMOS technology. Some testing experiments were conducted using the commercially available IC-type AD844s for evaluating the practical performance of the designed inverse filters.
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LOW-VOLTAGE TEMPERATURE-INSENSITIVE LOGARITHMIC AND EXPONENTIAL FUNCTION CURRENT GENERATORS USING ONLY NPN TRANSISTORS
(2025-01-31)
Pukkalanun, Tattaya
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Satansup, Jetsdaporn
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Maneerat, Sutassa
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Tangsrirat, Worapong
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Roongmuanpha, Natchanai
The continuing reduction of supply voltage for reliable operation of analog integrated circuits is widely recognized. Analog circuits must adhere to this trend. As a result, researchers are currently developing low-voltage analog circuit methodologies. Current-mode signal processing circuits are examples of these concepts. Therefore, the objective of this work is to present circuit realizations of low-voltage current-mode logarithmic and exponential function generators with temperature compensation. Both the input and output signals operate in current mode. The design approach utilizes the current-mode translinear technique to produce the output currents that exhibit a directly proportionality to the absolute values of the logarithmic and exponential functions. By simply adjusting the external bias currents, one can electronically tune the output currents and transfer current gains for both proposed circuits. The proposed circuits utilize only npn bipolar transistors and can operate with low-level supply voltages of ±1 V, which are appropriate for low-power, high-frequency applications. Nonideality performance considerations are also discussed in detail. In order to verify the operational function of the circuits and illustrate their superior thermal stability, the PSPICE simulation has been performed using real transistor models provided for the HFA3096 mixed bipolar array technology. The simulation findings illustrate that the proposed logarithmic and exponential amplifier circuits can compensate for temperature variations, as evidenced by the good stability of their output currents over a temperature range of –40 °C to 100 °C.
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Single-input three-output dual-mode universal biquad realization based on floating-current-source building blocks
(2017-11-03)
Mongkolwai, Pratya
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Unhavanich, Sumalee
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Tangsrirat, Worapong
A novel dual-mode universal biquadraic filter with one input and three outputs is presented, which contains only two floating current sources (FCSs), and four external passive components. The presented filter exhibits the following properties : capable of working either voltage-mode or current-mode, electronically controllable of the natural angular frequency (Ω<inf>o</inf>) by means of the transconductance gains, independent grounded-resistance control of the quality factor (Q), simultaneous realization of all the three basic filtering signals, no component matching constraints and low active and passive component sensitivities. To confirm the theory, the proposed circuit is simulated with PSPICE program using TSMC 0.25-μm CMOS technology.
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Three-input single-output current-mode universal filter using single CCCTA
(2017-07-01)
Budboonchu, Jakrawat
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Tangsrirat, Worapong
The circuit topology for the realization of a low- component count current-mode universal biquadratic filter with three inputs and single outputs (TISO) is described. The described structure employs a single current-controlled conveyor transconductance amplifier (CCCTA), and only two grounded capacitors, without needing any external passive resisotrs. By properly selecting the relevant input signal, the circuit is capable of generating the five standard biquadratic filtering functions, i.e. lowpass, bandpass, highpass, bandstop and allpass current responses. The proposed filter can also be electronically tuned by external bias currents of the CCCTA. The circuit is analyzed for the non-idealities of the used CCCTA and possesses attractive low sensitivity performance. Simulation results are found to be in good agreement with the theoretical analysis.
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Simple design technique for realizing low-voltage low-power CMOS current multiplier
(2015-01-01)
Tangjit, Jetwara
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Tangsrirat, Worapong
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Satansup, Jetsdaporn
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Surakampontorn, Wanlop
A simple circuit design technique for the realization of compact low-voltage low-power CMOS four-quadrant analog current multiplier circuit has been suggested. It is based on the use of the square-law characteristic in the NMOS current squaring function circuit operating in the saturation region. The suggested four-quadrant current multiplier circuit is designed for implementing in TSMC 0.25-μm CMOS technology with a low supply voltage of ±0.75V. To evaluate the circuit performance, the circuit has been simulated by PSPICE program. The simulation results show that the circuit has a linearity error of about 1%, a THD of 1.07% at 100 kHz, the total power consumption of 87.6 μW and -3dB bandwidth of 1.32 GHz.
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Current gain controlled CFTA and Its application to resistorless quadrature oscillator
(2012-10-02)
Prasertsom, Danucha
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Tangsrirat, Worapong
This paper presents the concept of the current follower transconductance amplifier (CFTA) with current gain controllable. The newly modified element is a combination of the current follower, the variable gain current mirror, and the balance output transconductance amplifier. The advantage of the proposed element is that the current transfer characteristics (i <inf>z</inf>/i <inf>f</inf> and i <inf>x</inf>/i <inf>z</inf>) can be electronically tuned by means of external bias currents. As application example, the resistorless realization of current-mode quadrature oscillator based on the proposed current controlled gain CFTA element is also presented. PSPICE simulation results of the proposed circuit and its application are given to confirm the theoretical analysis. © 2012 IEEE.
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CFTA-based current multiplier/divider circuit
(2011-12-01)
Mongkolwai, Pratya
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Tangsrirat, Worapong
In this paper, the design of a simple analog current-mode multiplier/divider circuit using only two current follower transconductance amplifiers (CFTAs) is presented. With the selection of the applied input currents, the proposed circuit can perform four-quadrant current multiplication, division and current-controlled current amplification, all from the same circuit configuration. The circuit is also insensitive to ambient temperature variations. Additionally, the CFTA non-ideality effects and the non-ideal gain and parasitic component effects on the proposed circuit are studied. The performances of the realized circuit are examined by PSPICE simulations. © 2011 IEEE.

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