Julsereewong, Amphawan

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Julsereewong, Amphawan
Alternative Name
Julsereewong, A.
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Email
amphawan.ju@kmitl.ac.th

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    A voltage/current controlled oscillator using OTAs and RS flip flop
    (2008-12-01)
    Pongswatd, Sawai
    ;
    Julsereewong, Amphawan
    ;
    Tirasesth, Kitti
    ;
    Sasaki, Hirofumi
    ;
    Shi, Yan
    This paper presents an electronic oscillator specially designed to be controlled in oscillation frequency by the control voltage and external bias current signals. The realization technique is simple and inexpensive based on the use of commercial available devices. The proposed circuit consists of operational transconductance amplifiers (OTAs) and an RS Flip Flop to generate tunable sawtooth and square waves. Experimental results verifying the performances of the proposed circuit are in close agreement with the expected values. An application example showing the usefulness of the proposed voltage controlled oscillator in phase-locked loop frequency synthesizer is also introduced. © 2008 SICE.
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    Interface circuit using operational conveyors for differential resistive sensors
    (2013-09-02)
    Julsereewong, Amphawan
    ;
    Julsereewong, Prasit
    ;
    Rungkhum, Tipparat
    ;
    Sasaki, Hirofumi
    In this paper, a simple and accurate circuit for interfacing differential resistive sensors is presented. The realization method employs three operational conveyors as active elements to provide voltage output linearly proportional to sensing resistance change. The performance is confirmed through PSPICE simulation and experimental results. © 2013 IEEE.
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    Simple linearization technique for remotely measuring resistance changes
    (2011-08-01)
    Julsereewong, Amphawan
    ;
    Julsereewong, Prasit
    ;
    Rungkhum, Tipparat
    ;
    Sasaki, Hirofumi
    ;
    Isoguchi, Hiroshi
    A simple linearization technique for remotely measuring resistance changes of single-element resistive-type sensors is presented in this article. The proposed circuit configuration uses commercially available devices to generate the output voltage, which is linearly proportional to the sensing resistance change. PSPICE simulation results are included to confirm not only the good operation but also the effective lead-resistance compensation of the proposed technique.
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    Simple VCO with negative voltage-frequency relation
    (2008-12-01)
    Pongswatd, Sawai
    ;
    Julsereewong, Amphawan
    ;
    Tirasesth, Kitti
    ;
    Sasaki, Hirofumi
    ;
    Shi, Yan
    A simple voltage controlled oscillator (VCO) with negative voltage-frequency (V-F) relation is presented in this paper. The realization technique is based on the use of commercial available devices to generate tunable sawtooth and square wave signals. Decreasing the control voltage linearly increases the output oscillation frequency. The proposed VCO consists of operational transconductance amplifiers (OTAs) and an RS Flip Flop. Experimental results showing the circuit performances are agreed with the expected values. The usefulness of the proposed circuit is demonstrated through application example with reducing the output ripple waveforms of a buck converter.
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    Design of a dual-input buck-boost converter for mobile back-lighting applications
    (2012-04-01)
    Eguchi, Kei
    ;
    Pongswatd, Sawai
    ;
    Julsereewong, Amphawan
    ;
    Oota, Ichirou
    ;
    Terada, Shinya
    For mobile back-lighting applications, a dual-input white LED (WLED) driver using a bi-direction buck-boost converter is proposed in this paper. The proposed driver has two input terminals: battery input V <inf>in1</inf> and solar-cell input V <inf>in2</inf>. Unlike conventional drivers using boost converters, step-up SC DC-DC converters, and so on, the proposed converter drives the anode and the cathode of LEDs by using the solar-cell's voltage and the negative stepped-down voltage, respectively. Furthermore, by converting solar energy, the proposed driver can charge a rechargeable battery when the LED backlight is standby mode. Therefore, the proposed driver can achieve long battery lifetime. The validity of the proposed driver is confirmed by SPICE simulations and experiments. SPICE simulations show that the proposed driver can offer the sufficient voltage to drive LEDs by using solar energy and battery energy in spite of the variation in V <inf>in2</inf>. Furthermore, by employing a bi-direction buck-boost converter, the proposed driver provides us to realize long battery lifetime, because the battery charge process was confirmed by experiments. © 2012 ICIC International.
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    Self-statable integral type astable multivibrator using CMOS-XOR/XNOR gates
    (2012-01-01)
    Sasaki, Hirotoshi
    ;
    Isoguchi, Hiroshi
    ;
    Yahara, Mitsutoshi
    ;
    Fujimoto, Kuniaki
    ;
    Julsereewong, Amphawan
    The astable multivibrator of the integral type operation using 2 CMOS-XOR/XNOR gates doesn't oscillate only by the power supply's being turned on. On the other hand, the proposed astable multivibrator of the integral type operation by 3CMOS-XOR/XNOR gates oscillates surely when the power supply is turned on. © 2012 The Institute of Electrical Engineers of Japan.
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    Simple monostable multivibrators using EX-OR/EX-NOR gates
    (2010-01-01)
    Riewruja, Vanchai
    ;
    Julsereewong, Amphawan
    ;
    Isoguchi, Hiroshi
    ;
    Sasaki, Hirofumi
    Two simple differential-type monostable multivibrators are proposed and demonstrated in this letter, where the first configuration operated under positive triggering mode utilizes EX-OR gates and the second configuration operated under negative triggering mode employs EX-NOR gates. Both realization methods make use of CMOS logic gates connected with a few passive elements to form as switching circuits. Experimental results show that the ranges of the output pulse widths are from several microseconds to milliseconds. © 2010 The Institute of Electrical Engineers of Japan.
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    Simple CCO using CCIIs and S-R latch and its application
    (2009-12-01)
    Chumkasean, Manop
    ;
    Julsereewong, Amphawan
    ;
    Pongswatd, Sawai
    ;
    Julsereewong, Prasit
    ;
    Sasaki, Hirofumi
    A simple circuit technique to realize current controlled oscillator (CCO) with two low-impedance input terminals is presented. By suitably setting two input signals, the linear frequency-current relation of the proposed CCO can be either positive or negative slope in the same circuit configuration. The oscillating output frequency proportional to the difference between two input currents can be also obtained. The realization method is employed second-generation current conveyors and Set-Reset latch. Experimental results verifying performances of the proposed CCO are in close agreement with expected values. To demonstrate the usefulness of the proposed oscillator, application example in current-mode variable-frequency control for buck converter is included. © 2009 IEEE.
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    A study on differential type monostable multivibrator using CMOS-XOR/XNOR gate
    (2011-01-01)
    Sasaki, Hirotoshi
    ;
    Julsereewong, Amphawan
    ;
    Isoguchi, Hiroshi
    ;
    Yahara, Mitsutoshi
    ;
    Fujimoto, Kuniaki
    In the differential type monostabel multivibirator using CMOS-XOR/XNOR gates, there is a circuit configuration that the operation of two elements becomes the same in stable sate and the metastable state. And, these circuits has the up mode and down mode operations. Furthermore, the metastable state is not influenced trigger repetition rate, and it is shown by a simple formula expression. © 2011 The Institute of Electrical Engineers of Japan.
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    Simple resistance-to-frequency converter with lead-wire-resistance compensation
    (2013-03-28)
    Julsereewong, Amphawan
    ;
    Petchmaneelumka, Wandee
    ;
    Rungkhum, Tipparat
    ;
    Yahara, Mitsutoshi
    ;
    Fujimoto, Kuniaki
    This article presents a simple technique to realize a resistance-to-frequency converter for single resistive sensor-based remote measurements. The proposed realization method uses commercially available devices to generate output frequency, which is linearly proportional to sensing resistance deviation. Experimental results are shown that not only the good circuit operation but also the effective lead-wire-resistance compensation of the proposed technique can be obtained. © 2013 ICIC International.