• Title/Summary/Keyword: current loop

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Load-Balance-Independent High Efficiency Single-Inductor Multiple-Output (SIMO) DC-DC Converters

  • Ko, Younghun;Jang, Yeongshin;Han, Sok-Kyun;Lee, Sang-Gug
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.3
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    • pp.300-312
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    • 2014
  • A single-inductor multiple-output (SIMO) DC-DC converter providing buck and boost outputs with a new switching sequence is presented. In the proposed switching sequence, which does not require any additional blocks, input energy is delivered to outputs continuously by flowing current through the inductor, which leads to high conversion efficiency regardless of the balance between the buck and boost output loads. Furthermore, instead of multiple output loop compensation, only the freewheeling current feedback loop is compensated, which minimizes the number of off-chip components and nullifies the need for the equivalent series resistance (ESR) of the output capacitor for loop compensation. Therefore, power conversion efficiency and output voltage ripples can be improved and minimized, respectively. Implemented in a 0.35-${\mu}m$ CMOS, the proposed SIMO DC-DC converter achieves high conversion efficiency regardless of the load balance between the two outputs with maximum efficiency reaching up to 82% under heavy loads.

Compact mobile antenna and near field characterization for Communication Broadcasting Convergence (통방융합용 소형 모바일 안테나 및 근거리장 특성)

  • Kang, Jeong-Jin;Rothwell, Edward J.
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.8 no.5
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    • pp.43-49
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    • 2008
  • Motivated by the Communication Broadcasting Convergence service, various technical approaches are being used to develop more efficient antenna models. This paper proposes a compact mobile antenna which is attachable to a cell phone and is applicable for Communication Broadcasting Convergence. In the design of the antennas for mobile handsets, size reduction is a crucial factor. In this paper, the compactness of a loop antenna is realized by bending a folded-dipole. A short planar dipole is transformed to a twice folded dipole and a loop antenna to produce a larger input resistance. The current distribution of the antenna is the same as a loop antenna, and its radiation patterns are omni-directional. We also analyze the performance of the RFID antenna by exploring the current-induced near field radiation patterns using a electro-optic field mapping system.

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Theoretical Analysis and Control of DC Neutral-point Voltage Balance of Three-level Inverters in Active Power Filters

  • He, Yingjie;Liu, Jinjun;Tang, Jian;Wang, Zhaoan;Zou, Yunping
    • Journal of Power Electronics
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    • v.12 no.2
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    • pp.344-356
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    • 2012
  • In recent years, multilevel technology has become an effective and practical solution in the field of moderate and high voltage applications. This paper discusses an APF with a three-level NPC inverter. Obviously, the application of such converter to APFs is hindered by the problem of the voltage unbalance of DC capacitors, which leads to system instability. This paper comprehensively analyzes the theoretical limitations of the neutral-point voltage balancing problem for tracking different harmonic currents utilizing current switching functions from the space vector PWM (SVPWM) point of view. The fluctuation of the neutral point caused by the load currents of certain order harmonic frequency is reported and quantified. Furthermore, this paper presents a close-loop digital control algorithm of the DC voltage for this APF. A PI controller regulates the DC voltage in the outer-loop controller. In the current-loop controller, this paper proposes a simple neutral-point voltage control method. The neutral-point voltage imbalance is restrained by selecting small vectors that will move the neutral-point voltage in the direction opposite the direction of the unbalance. The experiment results illustrate that the performance of the proposed approach is satisfactory.

Design and Reliability Analysis of Frequency Locked Loop Circuit with Symmetric Structure (대칭적 구조를 가진 주파수 고정 루프 회로의 설계 및 신뢰성 분석)

  • Choi, Jin-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.12
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    • pp.2933-2938
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    • 2014
  • In this paper, the FLL(Frequency Locked Loop) circuit using current conveyor circuit is designed by $0.35{\mu}m$ CMOS process. The FLL circuit is built in a frequency divider, a frequency-to-voltage converter, a voltage subtractor and a oscillator and the circuit blocks have a symmetric structure to improve a reliability characteristics with a process variation. From the simulation results, the variation rate of output frequency is about less than ${\pm}1%$ when the channel length, channel width, resistance and capacitance are varied ${\pm}5%$.

Control of the Buck Converter using the Function Control Law (함수제어 기법을 이용한 Buck 컨버터 제어)

  • 이성백;원영진;김태웅
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.11 no.6
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    • pp.81-89
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    • 1997
  • In order to achieve the zero voltage regulation of the output voltage, the function control law will be used. In the previous function control law, only the proportional controller is used and the stability of the closed loop system was not analyzed. In this paper, for the realization of the control law, a new method to retrieve the low frequency component of the inductor voltage is proposed and analyzed. The large signal closed loop characteristics are alos analyzed to ensure the stable operation of the system disturbances. By using the function control law in the control system, the effect of the disturbance of the supply voltage is reduced in 93.3% for the direct dusty ration method. Also, in the effect of the disturbance of the load current, the output voltage has a logn recovery-time and is changed proportionally in the direct duty ratio method, but has stable in the function control law. Finally, the analysis shows that the disturbance of the output voltage being due to the supply voltage variation can be eliminated completely and the closed loop output voltage is insensitive to the disturbance of the load current. Therefore, it is proved that by using the function control law, the switching power supply with zero-voltage regulation output voltage can be realized.

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A Study on DC-DC Power Supply for Magnetically Levitated Vehicle (자기부상열차용 DC-DC 전원장치에 관한 연구)

  • Chun, Choon-Byeon;Jeon, Kee-Young;Lee, Hoon-Goo;Han, Kyung-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.6
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    • pp.128-135
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    • 2004
  • The author present a modified multi-loop algorithm including feedforward for controlling a 55kW step down chopper in the power supply of Maglev. The control law for the duty cycle consists of three terms. The first is the feedforward term. which compensates for variations in the input voltaga. The second term consists of the difference between the slowly moving inductor current and output current. The third term consists of proportional and integral terms involving the perturbation in the output voltage. This perturvation is derived by subtracting the desired output voltage from the actual output voltage. The proportional and integral action stabilizes the system and minimizes output voltage error. In order to verify the validity of the proposed multi-loop controller, simulation study was tried using Matlab simulink

Optical Current Snesor using Faraday Effect (Faraday 효과를 이용한 광 전류 센서)

  • 김수길
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2002.11a
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    • pp.97-101
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    • 2002
  • The optical current transformer using Faraday effect is the sensor to measure current that flows in any conductor. This sensor doesn't undergo the magnetic saturation and effect of adjacent conductors. But this senor using bulk-glass sensing element has crucial drawback. It is impossible that the sensor is mounted to conductor without breaking the closed-loop of light or conductor. So we developed the clamp-type optical current transformer and made an experiment.

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Analog Multiplier Using Translinear Current Conveyor

  • Chaikla, Amphawan;Kaewpoonsuk, Anucha;Wangwi-wattana, C.;Riewruja, Vanchai;Jaruvanawat, Anuchit
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.80.1-80
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    • 2002
  • In this article, an alternative analog multiplier circuit, using the translinear second-generation current conveyors with the external resistors. The realization method makes use of the inherited translinear loop of the current conveyor offering the positive-supply current that provides in the quartersquare algebraic identity. The proposed circuit operates in voltage mode and it achieves a high accuracy. The PSPICE simulation results confirm that the performances of the proposed multiplier circuit, such as dynamic range and accuracy, are agreed with the theoretical results.

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Wide Range Analog Dual-Loop Delay-Locked Loop (광대역 아날로그 이중 루프 Delay-Locked Loop)

  • Lee, Seok-Ho;Kim, Sam-Dong;Hwang, In-Seok
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.44 no.1
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    • pp.74-84
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    • 2007
  • This paper presents a new dual-loop Delay Locked Loop(DLL) to expand the delay lock range of a conventional DLL. The proposed dual-loop DLL contains a Coarse_loop and a Fine_loop, and its operation utilizes one of the loops selected by comparing the initial time-difference among the reference clock and 2 internal clocks. The 2 internal clock signals are taken, respectively, at the midpoint and endpoint of a VCDL and thus are $180^{\circ}$ separated in phase. When the proposed DLL is out of the conventional lock range, the Coarse_loop is selected to push the DLL in the conventional lock range and then the Fine_loop is used to complete the locking process. Therefore, the proposed DLL is always stably locked in unless it is harmonically false-locked. Since the VCDL employed in the proposed DLL needs two control voltages to adjust the delay time, it uses TG-based inverters, instead of conventional, multi-stacked, current-starved inverters, to compose the delay line. The new VCDL provides a wider delay range than a conventional VCDL In overall, the proposed DLL demonstrates a more than 2 times wider lock range than a conventional DLL. The proposed DLL circuits have been designed, simulated and proved using 0.18um, 1.8V TSMC CMOS library and its operation frequency range is 100MHz${\sim}$1GHz. Finally, the maximum phase error of the DLL locked in at 1GHz is less than 11.2ps showing a high resolution and the simulated power consumption is 11.5mW.

Comparative Study between Two and Single-loop Control of Boost Converter for PVPCS (태양광용 부스트 컨버터의 2중 루프 제어 및 단일 루프 제어의 특성 비교)

  • Kim, Dong-Whan;Im, Ji-Hoon;Song, Seung-Ho;Choi, Ju-Yeop;An, Jin-Ung;Lee, Sang-Chul;Lee, Dong-Ha
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.153-159
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    • 2012
  • In photovoltaic system, the characteristic of photovoltaic module such as open circuit voltage and short circuit current will be changed because of cell temperature and solar radiation. Therefore, a boost converter of the PV system connects between the output of photovoltaic system and DC link capacitor of grid connected inverter as controlling duty ratio for maximum power point tracking(MPPT). This paper shows the dynamic characteristic of the boost converter by comparing single-loop control algorithm and two-loop control algorithm using both analog and digital control. The proposed both compensation method has been verified with computer simulation and simulation results obtained demonstrate the validity of the proposed control schemes.

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