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Short range electromagnetic interface using 0.35 μm CMOS blocks for temperature monitoring in isolated areas
(2022-11-01)
Sotner, Roman
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Jerabek, Jan
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Polak, Ladislav
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Prokop, Roman
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Ayten, Umut Engin
Introduction: Infra-red (IR) and visible light (VL) based systems developed for transmission of information about physical quantities (e.g. humidity, temperature) out from closed areas, cannot be effectively employed in case of specific conditions in a targeted environment (because of fog or vapor for example). Objectives: In this work, we introduce a concept of wireless short-range transmitter and receiver to sense physical quantities, for instance temperature, with slow variation. The proposed concept is able to transmit analog-based information from isolated environments (e.g. aquariums or environments for plant growing) with high immunity against vapor and fog that limits standard optical (laser, IR band) methods of communication. Methods: In this work, a new concept of short range radiofrequency (RF) communication device consisting of transmitting and receiving parts build from active devices fabricated in 0.35 μm I3T25 3.3 V CMOS process and ferrite antennas is selected. RF part uses medium-wave propagation within 10 mm distance at frequency 700 kHz. Such an approach offers minimal path loss of the radiated energy of a signal and low-gain amplification required for restoration of similar levels as available at the transmitting side. Results: The processing of base-band signals of simple (sine wave) and complex (electrocardiogram) character was verified experimentally through the system. Application example of temperature monitoring in a closed environment, based on a temperature sensor (thermistor), verifies operationability in temperature range from 10 °C up to 50 °C. Conclusion: Compared to state-of-the-art solution, the presented concept has several advantages, for instance: less complexity; using of simpler type of modulation and demodulation; lower power consumption and significantly reduced issues caused by an environment with special transmission conditions (e.g. fog and vapor). The obtained results are in good agreement with expectations. Among others, the presented system brings beneficial performances for similar applications targeting on monitoring of low-frequency or slowly varying signals.
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A Single Parameter Voltage Adjustable Immittance Topology for Integer- And Fractional-Order Design Using Modular Active CMOS Devices
(2021-01-01)
Sotner, Roman
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Jerabek, Jan
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Polak, Ladislav
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Prokop, Roman
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Jaikla, Winai
A simple single parameter adjustable immittance concept designed with modular active devices, fabricated in I3T $25~0.35~\mu \text{m}$ 3.3 V CMOS process of ON Semiconductor, is introduced. The proposed devices employ an integer-order capacitor and specifically designed fractional-order capacitors (sometimes called constant phase elements). The proposed active topology consists of two simple active elements, namely a linearly voltage adjustable operational transconductance amplifier and a voltage differencing unity gain voltage follower/buffer, and only two passive elements, i.e. redundancy is minimized. The designed topology offers generation of an adjustable immittance having both the capacitive and inductive character. The importance of the order as well as the value of the pseudo-capacitance for design and analyzes are shown, including all important parasitic features for estimation of expected operational bandwidth which have to be considered in the design. The operational bandwidth is determined by high values of approximants of fractional-order capacities (225, 56 and $8.8~\mu \text{F}$ /seĉ1- $\alpha $ , where $\alpha $ represents the order equal to 0.25, 0.5 and 0.75, respectively). These parameters result into ranges between tens of Hz and units-tens of kHz. The adjustability of the transconductance from 70 to $700~\mu \text{S}$ by the driving voltage between 0.05 and 0.5 V offers approximately one decade change of equivalent capacitance and inductance. Laboratory-based experiments done with a fabricated prototype confirmed the theoretical presumptions.
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Design of Second Order Lowpass and Bandpass Filter Using Single VDDDA and Its Modification as Sinusoidal Oscillator
(2019-12-01)
Kulapong, Worawut
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Siripongdee, Surapong
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Jaikla, Winai
This paper introduces an electronically controllable voltage mode analog biquad filter which is designed based on the series resistor-inductor-capacitor (RLC) topology. The proposed second order filter employs one active device, voltage differencing differential difference amplifier (VDDDA) and three passive elements (one resistor and two grounded capacitors). The natural frequency (\omega-{0}) is controlled electronically as well as quality factor (Q) by changing the bias current. Two filter responses, lowpass (LP) and bandpass (BP) functions with unity voltage gain are simultaneously achieved. The proposed voltage-mode biquad filter consists of two input voltage nodes with high impedance. These input voltages are employed to select the inverting or non-inverting filter response. The sinusoidal oscillator is realized by slight modification of the proposed voltage-mode biquad filter. The sinusoidal voltage output node is low impedance. With this configuration, the proposed sinusoidal oscillator can be connected to other circuits without requirement of the additional buffer devices. The proposed filter and sinusoidal oscillator employ a few in number of the passive and active devices (also with grounded capacitors). The proposed circuits are interesting for monolithic integrated circuit (IC) realization. Pspice simulation program and TSMC 0. 18m CMOS process parameters with ± 0.9V are employed to verify the functionality of the presented biquad filter and sinusoidal generator.
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Simple realization of quadrature sinusoidal oscillator with independent control
(2017-07-02)
Chaichana, Amornchai
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Jaikla, Winai
In this paper, a new sinusoidal oscillator is proposed. As a interesting feature, the proposed oscillator provides two sinusoidal voltage waveforms with 90° degree phase difference without the requirement of additional phase shifter circuit. The proposed circuit employs only a voltage differencing current conveyor (VDCC), three resistors and two grounded capacitors. The frequency of oscillation (FO) and condition of oscillation (CO) can be independently controlled. Also, the tuning of frequency of oscillation can be done electronically. The use of single active is highly attractive from integration point of view. PSPICE simulations using 0.18μm CMOS parameters and supply voltage of ±0.9V demonstrates a precise operation.
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A new quadrature sinusoidal oscillator for telecommunication system using VDDDAs
(2016-03-22)
Chaichana, Amornchai
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Jaikla, Winai
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Suwanjan, Peerawut
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Tuntrakool, Sunti
A CMOS voltage differencing differential difference amplifiers (VDDDAs) based voltage-mode quadrature sinusoidal oscillator is proposed. The proposed oscillator is based on the two integrator loop configuration with amplifier wherein the frequency of oscillation (FO) is tuned by the time constant of two integrator and the condition of oscillation (CO) is tuned by gain of amplifier. It is constructed from two VDDDAs, two resistors, and two grounded capacitors. With this structure, it is attractive to develop in monolithic chip. The tuning of frequency of oscillation can be electronically done without affecting the condition of oscillation. Also, the condition of oscillation can be adjusted by external resistor without affecting to frequency of oscillation. The simulation results have been demonstrated and discussed using parameters of 0.18um TSMC CMOS technology and +0.9V power supply voltages.
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New quadrature sinusoidal oscillator with amplitude controllability
(2014-01-01)
Chandee, Sasithon
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Jaikla, Winai
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Suwanjan, Peerawut
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Pookrongtong, Nattapon
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Kwawsibsam, Adisorn
The quadrature sinusoidal oscillator employing two voltage differencing tranconductance amplifiers (VDTAs) has been proposed. The condition of oscillation (CO) and frequency of oscillation (FO) can be independently controlled by adjusting the bias current of two VDTAs. The oscillator can provide two output voltages as quadrature waveform and one output current with magnitude controllability. It consists of two VDTAs and two grounded capacitors which is then suitable for IC architecture. The Pspice simulation results using 0.25μm TSMC CMOS parameters have justified the theoretical anticipation. © 2014 IEEE.
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Single active element based electronically controllable grounded inductance simulator
(2013-12-01)
Siriphot, David
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Maneewan, Suwat
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Jaikla, Winai
This article presents grounded inductance simulator using single current controlled current follower transconductance amplifier (CCCFTA) as active element. The simulated inductance value can be controlled electronically by adjusting the bias current of the CCCFTA. The grounded inductance simulator comprises one CCCFTA 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. © 2013 IEEE.

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