• Title, Summary, Keyword: Buck

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Dynamic Characteristics of DC-DC Converters Using Digital Filters

  • Kurokawa, Fujio;Okamatsu, Masashi;Ishibashi, Taku;Nishida, Yasuyuki
    • Journal of Power Electronics
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    • v.9 no.3
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    • pp.430-437
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    • 2009
  • This paper presents the dynamic characteristics of buck and buck-boost dc-dc converters with digital filters. At first, the PID, the minimum phase FIR filter and the IIR filter controls are discussed in the buck dc-dc converter. Comparisons of the dynamic characteristics between the buck and buck-boost converters are then discussed. As a result, it is clarified that the superior dynamic characteristics are realized in the IIR filter method. In the buck converter, the undershoot is less than 2% and the transient time is less than 0.4ms. On the other hand, in the buck-boost converter, the undershoot is about 3%. However, the transient time is approximately over 4ms because the output capacitance is too large to suppress the output voltage ripple in this type of converter.

Implementation of the high efficiency buck converter using the resonant circuit (공진회로를 이용한 고효율 Buc 컨버터의 구현)

  • 임승하;사공석진
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.11
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    • pp.167-174
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    • 1996
  • For the decreasing of switching loss, this paper designs the improved buck converter circuit and then compare with the conventional buck converter and finally analyzes the performance. When the switch is turn-off, in the buck converter using the smoothing capacitor, the flow of transient current and peak voltage having the high frequency components was generated because of the instantaneous open-state in the teminals of the switch. However, the buck converter presented in this paper eliminated this disadvantage by using the L-C circuit. Therefore, the higher PF in 0.85 is achieved than that of the buck converter using the smoothing capacitor. Also, due to the decreasing of the harmonic contain rate, the current usage rate is to be higher than that of the conventional buck converter by 4.48dB and the output voltage varient rate for the step response is to be lower 1.32 times than that of the conventional buck converter.

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Buck and Boost Photovoltaic Converter Driving Schemes under Low power level (태양광 저에너지 출력을 위한 Buck, Boost 컨버터 구동방식)

  • Kim, B.W.;Park, S.J.;Kim, K.H.;Son, M.H.;Cho, S.E.;Kim, C.U.
    • Proceedings of the KIPE Conference
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    • pp.669-672
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    • 2005
  • Normally, the buck converter is used for the charging converter of photovoltaic generator because this converter has good characteristics compare with boost and buck-booster converter But, in case of the sollar-cell voltage is lower than charging voltage, we cannot charge the sollar energy to the charger. So, in this paper, we proposed the novel hybrid converter using by combination of buck and boost converter for the charging converter of photovoltaic generator, as a results, it can operate buck, boost and buck-boost mode. The proposed novel converter has the same characteristics of the existent buck converter and furthermore it can operate as a boost converter. So, we can make the more effective photovoltaic charging system.

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Self-Excited Buck-Boost DC-DC Converter (자려식 승강압형 DC-DC 컨버터)

  • Lee, Seong-Gil;An, Tae-Yeong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.11
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    • pp.663-669
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    • 1999
  • This paper presents new self excited DC-DC converters such as Buck-boost type, Buck type and also non-inverting Buck-boost type. The proposed converters has the following advantages: simple topology, small number of circuit components, easy control method. Therefore, these converters are suitable for the portable appliances with battery source. It is especially suited for low power DC-DC conversion applications where non isolation output power is usually required. The steady state characteristics of proposed self exciting Buck-boost DC-DC converter are analysis and the result shows good agreement with experimental value. Furthermore the experimental results for 50W class self oscillating Buck-boost DC-DC converter have been obtained, which demonstrate the high efficiency and good performance.

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A CMOS Hysteretic DC-DC Buck Converter with a Constant Switching Frequency

  • Jeong, Taejin;Yoon, Kwang S.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.4
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    • pp.471-476
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    • 2015
  • This paper describes a CMOS hysteretic DC-DC buck converter with a constant switching frequency for mobile applications. The inherent problems of a large output ripple voltage that the conventional hysteretic DC-DC buck converters has faced have been resolved by using the proposed DC-DC buck converter which employed a ramp generator circuit to be able to increase a switching frequency. The proposed architecture enables the settling response time of charge pump circuit within the converter to become less than 6us suitable for mobile applications. The proposed DC-DC buck converter was implemented by using 0.35 um BCDMOS process and die size was $1.37mm{\times}1.37mm$. The measurement results showed that the proposed circuit received the input of 3.7 V and generated output of 1.2 V with the output ripple voltages less than 20 mV under load currents of 100~400 mA at the fixed switching frequency of 2 MHz. The maximum efficiency of the proposed hysteretic buck converter was measured to be around 93%.

Response Characteristics Of DC-DC Buck Converter Analysis and Research (DC-DC Buck Converter의 응답특성 해석 및 연구)

  • Lee, Kyung-Hoan;Kim, Jin-Deok
    • Proceedings of the KIPE Conference
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    • pp.28-29
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    • 2013
  • DC-DC Buck Converter는 입력 전압보다 출력전압이 낮은 컨버터이며 강압형 컨버터라고도 한다. 입력과 출력이 같은 접지를 공유하는 회로에 쓰이며, 스위칭 소자를 이용하여 듀티비에 따라 출력전압을 제어할 수 있고, 출력단의 LC 필터를 통해 평활(평균)하여 직류전압을 얻을 수 있다. DC-DC Buck Converter는 제어가 간단하고 설계가 쉬워 주로 회로의 파워부에 많이 쓰이고 있으며, 본 논문에서는 DC-DC Buck Converter의 기본형과 2Stage DC-DC Buck Converter 그리고 기본형의 GND단에 L을 추가한 DC-DC Buck Converter의 응답특성을 비교 및 분석을 함으로써 이론적 해석과 시뮬레이션을 통한 특성을 비교 하고자 한다.

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Buck converter using a non-dissipative snubber (탭-인덕터 적용 무손실 스너버에 의한 Buck 컨버터)

  • Park S. S.;Kong Y. S.;Yang S. C.;Kim E. S.
    • Proceedings of the KIPE Conference
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    • pp.154-158
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    • 2003
  • This paper presents an improved soft switching buck converter using a non-dissipative snubber, which is composed of a tapped inductor, two snubber capacitors and three snubber diodes. The proposed buck converter achieves zero voltage turn-off in the main switch and freewheeling diode. The Proposed Soft Switching buck converter is verified through the simulation, relevant equations, analysis and experimental results.

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Buck and Half Bridge Series DC-DC Converter (강압형과 하프 브리지 직렬형 DC-DC 컨버터)

  • Kim Chang-Sun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.12
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    • pp.616-621
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    • 2005
  • We considered of the buck and half bridge series DC-DC converter. It has good applications in areas with low voltage/high current, wide input voltage. The buck converter ratings and the half bridge converter ratings are $36\~72V$ input and 22V/5A output, $19\~24V$ input and 3.3V/30A output, respectively. Developed the buck and half Bridge series DC-DC converter ratings are of $36\~72V$ input and 3.3V/30A output. The buck converter is operated with zero voltage switching process to reduce the switching losses. The $80.1\%\~97.6\%$ of the efficiency is measured at $18.4{\mu}H$ output filter inductance of buck converter. In the half bridge converter, the $86\%\~96.4\%$ efficiency is measured at 150kHz switching frequency with PQI core. In the case of synchronized the buck and half bridge DC-DC converter, the measured efficiency is higher than that of the unsynchronized converter. In the synchronized converter, the maximum efficiency is measured up to $92.3\%$ with PQI core at 150kHz. 7A output.

A Buck-Boost Type Charger with a Switched Capacitor Circuit

  • Wu, Jinn-Chang;Jou, Hurng-Liahng;Tsai, Jie-Hao
    • Journal of Power Electronics
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    • v.15 no.1
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    • pp.31-38
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    • 2015
  • In this paper, a buck-boost type battery charger is developed for charging battery set with a lower voltage. This battery charger is configured by a rectifier circuit, an integrated boost/buck power converter and a switched capacitors circuit. A boost power converter and a buck power converter sharing a common power electronic switch are integrated to form the integrated boost/buck power converter. By controlling the common power electronic switch, the battery charger performs a hybrid constant-current/constant-voltage charging method and gets a high input power factor. Accordingly, both the power circuit and the control circuit of the developed battery charger are simplified. The switched capacitors circuit is applied to be the output of the boost converter and the input of the buck converter. The switched capacitors circuit can change its voltage according to the utility voltage so as to reduce the step-up voltage gain of the boost converter when the utility voltage is small. Hence, the power efficiency of a buck-boost type battery charger can be improved. Moreover, the step-down voltage gain of the buck power converter is reduced to increase the controllable range of the duty ratio for the common power electronic switch. A prototype is developed and tested to verify the performance of the proposed battery charger.

Direct Current Control Method Based On One Cycle Controller for Double-Frequency Buck Converters

  • Luo, Quanming;Zhi, Shubo;Lu, Weiguo;Zhou, Luowei
    • Journal of Power Electronics
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    • v.12 no.3
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    • pp.410-417
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    • 2012
  • In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.