Montree Kumngern

DDCC-Based Quadrature Oscillator with Grounded Capacitors and Resistors

A new voltage-mode quadrature oscillator using two differential difference current conveyors (DDCCs), two grounded capacitors, and three grounded resistors is presented. The proposed oscillator provides the following advantages: the oscillation condition and oscillation frequency are orthogonally controlled; the oscillation frequency is controlled through a single grounded resistor; the use of only grounded capacitors and resistors makes the proposed circuit ideal for IC implementation; low passive and active sensitivities. Simulation results verifying the theoretical analysis are also included.

High frequency and high precision CMOS full-wave rectifier

This paper describes a high frequency and high precision full-wave rectifier using a fully differential input and output operational transconductance amplifier (FDIO-OTA), which is very suitable for CMOS technology implementation. The system comprises a voltage to current converter, precision full-wave rectifier and a current-to-voltage converter. An input voltage signal is converted into two symmetrical current signals by using a FDIO-OTA. Two current signals will be rectified by using MOS diodes and convert into output voltage by using grounded MOS resistor. The circuit exhibits a very precise rectifier and very high operating frequency. The simulation results demonstrate the performance of the proposed circuit.

New electronically tunable current-mode universal biquad filter using translinear current conveyors

In this study, a new electronically tunable current-mode universal filter with two inputs and two outputs employing one translinear current conveyor, one translinear current conveyor with controlled current gain and two grounded capacitors is presented. The proposed circuit offers the following attractive features: realisation of low-pass, band-pass, high-pass, band-stop and all-pass current responses from the same configuration; employment of the minimum active and passive components; no requirement of component matching conditions; independent current-control of the parameters natural frequency (ωo) and quality factor (Q); low active and passive sensitivities; and high impedance output. The characteristics of the proposed circuit are simulated using PSPICE to confirm the theory.

A sinusoidal oscillator using translinear current conveyors

This paper presents a new single-element-controlled current-controlled sinusoidal oscillator. The proposed oscillator is composed of one translinear current conveyor (CCCII), one CCCII with controlled current gain and two grounded capacitors. The oscillator is beneficial to monolithic integrated circuit implementation by the use of grounded capacitors. The oscillation condition and the oscillation frequency can be controlled electronically and independently through the bias current of the CCCII. PSPICE simulation results are given to confirm the operation of the proposed oscillator.

Current‐mode quadrature oscillator using current differencing transconductance amplifiers

This article presents a new electronically tunable single‐element‐controlled current‐mode quadrature sinusoidal oscillator circuit using current differencing transconductance amplifiers (CDTAs). The proposed oscillator is consisted of two CDTAs, two grounded capacitors and one grounded resistor, which is beneficial to monolithic integrated circuit implementation both in CMOS and bipolar technologies. The condition of oscillation and the frequency of oscillation are independently controllable. The frequency of oscillation can also be electronically controlled by adjusting the bias current of CDTA. The circuit provides four quadrature current outputs and two quadrature voltage outputs. The current output terminals possess high impedance level. PSPICE simulation results are used to verify the performance of the proposed circuit implemented at the transistor level. The measurement results support the computer simulations.

Electronically tunable voltage-mode universal filter with three-input single-output

A new electronically tunable voltage-mode universal filter with three-input single-output using six simple CMOS operational transconductance amplifiers and two capacitors is proposed. The proposed filter provides lowpass, bandpass, highpass, bandstop and allpass voltage responses. Also, the parameters ωo and Q can be set orthogonally by adjusting the circuit components. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.

Voltage-mode low-pass, high-pass, band-pass biquad filter using simple CMOS OTAs

A high input impedance electronically tunable voltage-mode biquadratic filter with single input and three outputs using four simple CMOS operational transconductance amplifiers and two grounded capacitors is proposed. The proposed filter provides low-pass, band-pass and high-pass voltage responses at a high input impedance terminal, which enables easy cascadability of the voltage circuit. Also, the parameters ωo and Q can be set orthogonally by adjusting the circuit components. For the realizing of all the filter responses, no critical matching condition is required, on inverting-type input signal is imposed and all the incremental parameter sensitivities are low. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory. The band-stop and all-pass responses can also be obtained by interconnection of relevant output voltages with summer circuits.

Comparative study of sub-volt differential difference current conveyors

Enhancing the performances of analog circuits with sub-volt supplies becomes a great challenge for circuit designers. Techniques such as bulk-driven (BD) and quasi-floating gate (QFG) count among the suitable ones for ultra-low voltage (ULV) operation capability with extended input voltage range and simple CMOS circuitry. However, in comparison to the conventional gate-driven (GD) MOS transistor (MOST), these techniques suffer from several disadvantages such as low transconductance value and bandwidth that limit their applicability for some applications. Therefore, the idea of merging the BD and QFG techniques to eliminate their drawbacks appears as efficacious solution. This new merging is named bulk-driven quasi-floating gate (BD-QFG)* technique and in order to demonstrate its advantages in compassion to BD and QFG ones, this paper presents a comparison study of three ULV differential difference current conveyor (DDCC) blocks based on BD, QFG and BD-QFG techniques. The significant increment of the transconductance and the bandwidth values of the BD-QFG are clearly observed. The proposed CMOS structures of the DDCCs work at ?300mV supply voltage and 18.5?W power consumption. The simulation results using 0.18?m CMOS n-Well process from TSMC show the features of the proposed circuits.

Voltage-mode multifunction biquadratic filter based on simple CMOS OTAs

A voltage-mode versatile multifunction filter with four inputs and three outputs biquadratic filter based on simple CMOS operational transconductance amplifiers (OTAs) is presented. By appropriately connecting the input and output terminals, the proposed circuit can work as either a single-input multiple-output (SIMO) or a multiple-input single-output (MISO) filter without changing the circuit topology. When the circuit functions as a SIMO filter, it provides bandpass (BP), lowpass (LP) and bandstop (BS) voltage responses with grounded capacitors. When it functions as a MISO filter, the circuit can realize all the standard non-inverting and inverting second-order filter functions. The parameters ω0 and Q can be set orthogonally by adjusting the circuit components. For realizing all the filter responses, no critical matching condition is required, no inverting-type input signal is imposed and all the incremental parameter sensitivities are low. The simulation results confirm the theoretical analysis.

Current-mode third-order quadrature oscillator using minimum elements

This paper presents a new current-mode third-order quadrature oscillator. The proposed circuit, which uses one current-controlled current differencing transconductance amplifier (CCCDTA), one operational transconductance amplifier (OTA) and three grounded capacitors, can generate two quadrature voltage outputs and two quadrature current outputs. The oscillation condition and the oscillation frequency can be controlled orthogonally and electronically by adjusting the bias currents of the CCCDTA and OTA. The use of only grounded capacitor makes the proposed circuit ideal for integrated circuit implementation. Simulation results verifying the theoretical analysis are also included.