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Temperature Compensation for Transformer-type Transducer
(2021-01-01)
Songsuwankit, Kanoknuch
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Riewruja, Vanchai
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Watanachaturaporn, Pakorn
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Rerkratn, Apinai
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Petchmaneelumka, Wandee
A novel technique to compensate the temperature effect of a transformer-type transducer is proposed in this paper. The effect of the ambient temperature on the transformer-type transducer is investigated from a primary-winding current. The advantage of the proposed technique is that the temperature effect is compensated without requiring a temperature sensor, making it suitable for applications in robotic and automation systems operated in harsh environments. The primary-winding current of the transducer is generated using a second-generation current conveyor (CCII). The excitation signal of the transformer-type transducer is driven by the CCII and the current flowing through the primary winding is transferred to an output signal of the CCII. The deviation of the primary-winding current due to the temperature effect is evaluated from the output signal of the CCII. The temperature effect on the transducer is manipulated by a closed-loop principle using a subtract-and-sum action instead of a traditional proportional-plusintegral action to eliminate the deviation of the primary-winding current. Therefore, the temperature effect on the transducer is compensated. A linear variable differential transformer (LVDT) is used to demonstrate the proposed technique, whose performance is discussed in detail and confirmed experimentally. All devices used in this experiment are commercially available. Experimental results show that the measured error of the output signal from the LVDT at 70 C can be reduced from 6.2% without temperature compensation to 0.06% by using the proposed technique, which has the advantages of a low cost, simple configuration, and high performance.
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Simple and low-cost readout circuit for differential resistive sensors
(2018-09-01)
Katman, Ratchanoo
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Rerkratn, Apinai
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Kaewpoonsuk, Anucha
In this paper, a simple and low-cost readout circuit for differential resistive sensors is presented. The realization method is based on the relaxation oscillation technique, which utilizes the operational amplifiers (op-amps) with a single supply voltage. The oscillating output Duty-Cycle is proportional to the difference of two sensing resistances. In comparison with the traditional voltage divider circuit or the Wheatstone bridge circuit or the previously reported readout circuit based on CCIIs, the proposed circuit can be interfaced with microcontroller without using an analog-to-digital converter. Theoretical predictions are supported by the PSPICE simulation results and the experimental data. In applying a slide potentiometer with changes of slider positions of ±15 mm, it is found that the maximum error of the proposed circuit is approximately-2.90% of full-scale. Copyright © 2018 Praise Worthy Prize S.r.l.-All rights reserved.
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Simple DC-excited resistance-to-period converter using CFOAS
(2018-05-01)
Kaewpoonsuk, Anucha
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Katman, Ratchanoo
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Rerkratn, Apinai
This paper presents a new method to implement a resistance-to-period converter for DC-excited resistive sensor. The proposed technique makes use of the characteristic of a controllable unity-gain inverting/non-inverting amplifier formed by current feedback operational amplifiers (CFOAs). Experimental results that verify the performance of the proposed circuit are also included.
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Feedforward bulk-driven class AB fully-differential second-generation current conveyor (FDCCII)
(2014-01-01)
Thongleam, Thawatchai
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Kasemsuwan, Varakorn
In this paper, a feedforward bulk-driven class AB fully-differential second-generation current conveyer (FDCCII) is presented. Bulk-driven differential pair is employed for the input stage allowing the FDCCII to operate with rail-to-rail operation. Feedfoward technique is also incorporated into input stage to increase the DC gain and minimize the common mode gain. The circuit performance is verified using HSPICE in 0.18 μm CMOS technology. The simulation results show rail-to-rail input and output swings. The DC voltage transfer characteristic between ports Y and X and DC current transfer characteristic between ports X and Z shows good linearity. The bandwidths show 25.7 MHz (V<inf>X</inf>/V<inf>Y</inf>), 30 MHz (I<inf>Z</inf>/I<inf>X</inf>), respectively. The power dissipation is 267.5 μW. © (2014) Trans Tech Publications, Switzerland.
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CMOS precision full-wave rectifier using current conveyor
(2010-12-01)
Kumngern, Montree
This paper presents a precision full-wave rectifier, which is highly suitable for CMOS technology implementation. The system comprises a voltage-to-current converter, precision full-wave rectifiers and a current-to-voltage converter. An input voltage signal is converted into two symmetrical current signals by using a dual-output second generation current conveyor. Two current signals will be rectified by using junction diodes and convert into output voltages by using grounded MOS resistors. Simulated rectifier results based on a 0.5μm CMOS technology demonstrates very high operating frequency and very precise rectification. © 2010 IEEE.
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Dual slope analog-to-digital converter using simple CCII-based integrator
(2010-10-01)
Smerpitak, Krit
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Julsereewong, Amphawan
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Sasaki, Horofumi
This article presents a dual slope analog-to-digital converter (ADC) using second generation current conveyor (CCII)-based integrator. In comparison with the previously reported dual slope ADCs with grounded capacitor, the proposed configuration offers simpler structure and fewer components while utilizing the positive reference voltage. Experimental results are given to confirm the operation of the proposed ADC. ICIC International © 2010 ISSN.
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Simple CCO using cciis and S-R latch and its application
(2010-06-01)
Smerpitak, Krit
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Julsereewong, Amphawan
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Pongswatd, Sawai
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Sasaki, Hlrofumi
This article presents a, simple circuit technique based on commerciallyavailable devices to realize current controlled, oscillator (CCO) with twolow-impedance input terminals. By suitably setting two input signals, the linearfrequency-current relation of the proposed CCO can be either positive ornegative slope in the same circuit configuration. The oscillating outputfrequency linearly proportional to the difference between two input currents canbe obtained. The realization method is employed in second-generation currentconveyors (CCIIs) and, Set-Reset (S-R) latch. Experimental results verifyingperformances of the proposed, CCO are closely agreed, with expected, values. Toshow the usefulness of the proposed, oscillator, an application example incurrent-mode variable- frequency control for buck converter is also included.ICIC International © 2010.
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Enhanced differential voltage-to-Frequency converter for telemetry applications
(2010-01-01)
Petchmaneelumka, Wandee
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Julsereewong, Amphawan
This paper presents an enhanced differential voltage-to-Frequency (dVFC) suitable for telemetry applications. The realization method employs op-amps in conjunction with current conveyors and Set-Reset latch. The converter gain can be easily adjusted through the variation of a single resistor. Compared to the previous dVFC using only current conveyors and Set-Reset latch, the proposed converter offers significant improvements in accuracy and circuit configuration. Its benefits are higher accuracy, simpler structure, fewer components, and lower costs. Experimental results verifying performances of the proposed dVFC are closely agreed with expected values. © 2010 SICE.
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Current-conveyor-based single-element-controlled and current-controlled sinusoidal oscillators
(2006-07-01)
Fongsamut, C.
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Anuntahirunrat, K.
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Kumwachara, K.
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Surakampontorn, W.
A new single-element-controlled sinusoidal oscillator circuit that incorporates two second generation current conveyors (CCIIs), two grounded capacitors and two resistors is presented and analysed. The circuit is beneficial to monolithic integrated circuit implementation by the use of grounded capacitors. In addition, a new current-controlled sinusoidal oscillator using only two second generation current controlled conveyors (CCCIIs) and two grounded capacitors can be achieved by replacing CCIIs and resistors series at X terminals with CCCIIs. The oscillators provide extremely low passive 0 -sensitivities and good frequency stability. Moreover, the oscillation frequencies of the CCII-based and the CCCII-based oscillators can be controlled, respectively, by a grounded resistor and by an external bias current. Experimental and SPICE simulation results that confirm the theoretical predictions are given.
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The describing function method and the analysis of the magnitude stabilization phenomenon in a nonlinear OSC
(2005-12-01)
Pranayanuntana, Poramate
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Anuntahirunrat, Kongsak
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Fongsamut, Chalermpan
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Kaewsaiha, Pongrapee
We present a nonlinear analysis of a non-linear oscillator which uses an operational transconductance amplifier (OTA), a second generation current conveyor (CCII), or a current feedback operational amplifier (CFOA) as a nonlinear element. Nonlinear oscillators are nonlinear systems that can display oscillations of fixed amplitude and fixed period without external excitation. These oscillations are called limit cycles, or self-excited oscillations. The magnitude stabilization phenomenon in a nonlinear oscillator is one of the characteristics of stable limit cycles. An equivalent feedback configuration of an oscillator circuit with a nonlinear feedback element is used. The essential tool here is the describing function method used for predicting the existence of limit cycles and, more generally, used to analyze the magnitude stabilization phenomena. We motivate this method for the physical insights into the analysis and design of nonlinear oscillator circuits based on nonlinear devices such as OTA, CCII, CFOA, etc. The describing function method offers also a way for finding the magnitude of an oscillation via an integral equation. Simulation results using MATLAB and PSPICE agree well with the theory. © 2005 IEEE.

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