Pongswatd, Sawai

Preferred name

Pongswatd, Sawai

Alternative Name

Pongswatd, S.

Main Affiliation

School of Engineering

sawai.po@kmitl.ac.th

Now showing 1 - 10 of 31

Some of the metrics are blocked by your
consent settings
Design of a multiple-input parallel SC DC-DC converter and its efficiencyestimation method
(2009-09-01)
Eguchi, Kei
;
Sugimura, Tatsuya
;
Pongswatd, Sawai
;
Tirasesth, Kitti
;
Sasaki, Hirofumi
A multiple-input parallel SC (Switched Capacitor) DC-DC converter and itsefficiency estimation method are proposed in this paper. The proposed parallelconverter consists of two different kinds of converter blocks: 1. a 1.5×step-up SC DC-DC converter employing an input voltage from a lithium battery and2. a novel step-up converter employing an input voltage from clean energysupplies. Since the proposed step-up converter can achieve not only a largestep-up conversion ratio but also a wide input range, the proposed parallelconverter enables us to extend battery runtime, reduction of heat, and so on.Furthermore, concerning the proposed converter, theoretical analyses areperformed to estimate power efficiency. The proposed analysis technique can beextended to the circuit design of other SC DC-DC converters. The validity ofcircuit design and theoretical formulas is confirmed by SPICE simulations.ICIC International © 2009.
Some of the metrics are blocked by your
consent settings
Design of 5x step-up sc dc-dc converter for industrial wireless transmitter
(2011-08-01)
Pongswatd, Sawai
;
Kunsri-U-Chane, Kachane
;
Smerpituk, Krit
;
Eguchi, Kei
;
Sasaki, Hirofumi
In this paper, a 5x step-up switched-capacitor (SC) DC-DC converter utilizing solar energy for industrial wireless transmitters is presented. A wireless transmitter can be supplied by its internal battery in combination with the proposed converter for long battery runtime. A Rosemount wireless transmitter from Emerson Process Management Company is used as a target application example in process measurement. The proposed converter is designed for receiving 1.5 V solar cells and powering 7.5 V connected in parallel with wireless transmitter battery. The validity of circuit design is conrmed by theoretical analysis and SPICE simulation. The derived formulas will be helpful to estimate circuit characteristics. Moreover, SPICE simulation values agree well with theoretical results.
Some of the metrics are blocked by your
consent settings
Parallel 5x step-up SC DC-DC converter for power efficiency improvement
(2011-01-01)
Pongswatd, Sawai
;
Smerpituk, Krit
;
Eguchi, Kei
;
Sasaki, Hirofumi
In switched-capacitor converter, the fluctuation of on-resistance effects power efficiency in proportion to the decrease of output load. This paper presents switched-capacitor (SC) DC-DC converter that parallel-connected to improve the power efficiency. The converter utilizes solar energy for industrial wireless transmitter. It can be supplied by its internal battery in combination with the proposed converter for long battery runtime. A Rosemount wireless transmitter from Emerson Process Management Company is used as a target application example in process measurement. The proposed converter is designed for receiving 1.5 V solar cells and powering 7.5 V connect in parallel with wireless transmitter battery. The validity of the theoretical analyses is confirmed by SPICE simulations and experimental results. The derived formulas will be helpful to estimate circuit characteristics. Moreover, SPICE simulation values and experimental results agree well with theoretical results. © 2011 SICE.
Some of the metrics are blocked by your
consent settings
Design of a switched-capacitor-based serial DC-DC converter using clean energy power supplies
(2010-07-30)
Eguchi, Kei
;
Pongswatd, Sawai
;
Sugimura, Tatsuya
;
Thepmanee, Teerawat
;
Tirasesth, Kitti
For mobile back-lighting applications, a switched-capacitor-based serial DC-DC converter using solar power supplies is proposed in this paper. Unlike conventional switched-capacitor DC-DC converters, the proposed converter pushes up the output voltage of a switched-capacitor-based circuit by the voltage of solar cells. For this reason, the proposed converter can realize not only long battery runtime but also small hardware-cost and wide input-range. Concretely, in comparison with the conventional parallel converter using 1.5× step-up SC converters, the proposed converter can achieve 20% reduction of hardware cost and 16% extension of input range. The characteristics of the proposed converter are clarified by theoretical analyses. Furthermore, SPICE simulations and experiments show the validity of circuit design, where theoretical results correspond well with simulation results.
Some of the metrics are blocked by your
consent settings
Design of a dual-input SC DC-DC converter realizing negative outputs
(2011-01-01)
Eguchi, Kei
;
Pongswatd, Sawai
;
Tirasesth, Kitti
;
Sasaki, Hirofumi
;
Zhu, Hongbing
Aimed at a back-lighting application, a dual-input switched-capacitor (SC) DC-DC converter with battery charge process is proposed in this paper. The proposed converter can realize -1/N× (N = 2,3,.) step-down conversion as well as (N + 1)/N× step-up conversion. By converting clean energy such as solar energy, the proposed dual-input converter not only drives light-emitting diodes (LEDs) but also recharges the battery, although conventional single-input converter only consumes battery energy. In the proposed converter, the -1/N× stepped-down voltage is generated to drive the LED's cathode when the input voltage is insufficient to drive a 1× transfer mode. Furthermore, unlike conventional converters, the battery is charged by the (N + 1)/N× stepped-up voltage when the LED back light is in standby mode. Hence, the proposed converter can realize long battery run time. The validity of circuit design is confirmed by theoretical analyses, simulations, and experiments. The derived theoretical formulas will be helpful to estimate circuit characteristics, because the theoretical results correspond well with the simulation program with integrated circuit emphasis (SPICE) simulation results. © 2011 Institute of Electrical Engineers of Japan.
Some of the metrics are blocked by your
consent settings
Design of step up and down Bi-directional switched capacitor DC-DC converter
(2012-02-01)
Pongswatd, Sawai
;
Smerpituk, Krit
;
Eguchi, Kei
;
Sasaki, Hirofumi
This paper presents the design technique to implement a DC-DC converter that can convert input voltage with step-up or step-down, and bi-directional power flow. The conversion ratio and power efficiency of the converter can be specified by circuit structure, which has capacitors connected in parallel or series configuration. The conversion ratios of step up and step down are 2x, 3x, 4x,... and 1/2x, 1/3x, 1/4x,..., respectively. The direction of power flow can be controlled by state of input and output switches. SPICE simulation results show that output voltage and power efficiency of the proposed converter agree well with theoretical values. © 2012 ICIC International.
Some of the metrics are blocked by your
consent settings
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.
Some of the metrics are blocked by your
consent settings
A multiple-input SC DC-DC converter with battery charge process
(2009-12-01)
Eguchi, Kei
;
Pongswatd, Sawai
;
Zhu, Hongbing
;
Tirasesth, Kitti
;
Sasaki, Hirofumi
Aimed at a backlighting application, a multiple-input switched-capacitor (SC) DC-DC converter with battery charge process is proposed in this paper. Unlike conventional SC power converters such as a Dickson-type converter, etc., the proposed converter drives some LEDs by converting energy from solar cells when solar cells offer enough energy. Furthermore, the proposed converter can charge a lithium battery when an output load is light. Hence, the proposed converter enables us to realize long battery runtime. The validity of circuit design is confirmed by theoretical analyses, simulations, and experiments. The derived theoretical formulas will be helpful to estimate circuit characteristics, because theoretical results agree well with SPICE simulation results. © 2009 IEEE.
Some of the metrics are blocked by your
consent settings
Power saving techniques to improve efficiency of a parallel-connected negative DC-DC converter
(2013-09-02)
Eguchi, Kei
;
Pongswatd, Sawai
;
Thepmanee, Teerawat
;
Fujimoto, Kuniaki
;
Sasaki, Hirofumi
A parallel-connected negative DC-DC converter using power saving techniques has been proposed in this paper. Unlike conventional negative converters, the proposed converter consists of four negative heap converters connected in parallel, where the power switch is driven by non-overlapped four-phase pulses cyclically. In two of the four negative heap converters, a part of the electric charge in parasitic capacitances is reused in each clock cycle. For this reason, the proposed converter can reduce energy loss than the conventional converters. The validity of the proposed technique was confirmed by simulation program with integrated circuit emphasis (SPICE) simulations and theoretical analysis. When the output load is 1 km, the proposed converter was able to improve power efficiency more than 11% compared to the conventional converter. © 2013 IEEE.
Some of the metrics are blocked by your
consent settings
Synthesis and analysis of a multiple-input parallel SC DC-DC converter
(2009-10-22)
Eguchi, Kei
;
Pongswatd, Sawai
;
Tirasesth, Kitti
;
Sasaki, Hirofumi
As compared with parallel converters employing buck converters or boost converters, the analysis of multiple-input parallel switched-capacitor (SC) DC-DC converters is not sufficient. In this paper, a multiple-input parallel DC-DC converter designed by using SC techniques is proposed for mobile back-lighting applications, and handy theoretical formulas are given concerning the power efficiency and equivalent circuit. The proposed parallel converter consists of two different kinds of converter blocks: 1. a 1.5x step-up SC DC-DC converter employing an input voltage from a lithium battery and 2. a novel step-up converter employing an input voltage from solar cells. The proposed converter can offer the output voltage for display back-lighting from solar energy, because the proposed step-up converter can achieve not only a large step-up conversion ratio but also a wide input range. Hence, the proposed converter will enable us to realize a long battery life, reduction of heat, and so on. Furthermore, derived theoretical formulas will be helpful to estimate circuit characteristics, because theoretical results agree well with SPICE simulation results. The validity of circuit design is confirmed by simulations and experiments. ©2009 IEEE.

Pongswatd, Sawai

Filters

Settings

Sort By

Results per page