• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1155-1161
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• 2014

This paper proposes a start-up voltage generator for reducing the minimum input supply voltage of DC-DC boost converters to 250mV. The proposed start-up voltage generator boosts 250mV input voltage to over 500mV to charge the capacitor for starting the boost converter. After the boost converter operates initially with the supply voltage charged in the capacitor, it uses its boosted output voltage for the supply voltage. Therefore, after the start-up operation, the proposed DC-DC boost converter works as the same as the conventional one. The proposed start-up voltage generator reduces the threshold voltage of the transistors by adjusting the body voltage at a low input voltage. This causes the higher clock frequency and the larger current to a Dickson charge-pump for boosting the input voltage. The proposed start-up voltage generator was implemented with a $0.18{\mu}m$ CMOS process. Its clock frequency and output voltage were 34.5kHz and 522mV at 250mV input voltage, respectively.

• Journal of IKEEE
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• v.18 no.2
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• pp.220-227
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• 2014

This paper presents a control method of Single-Inductor Dual-Output DC-DC Converter using Common mode feedback and differential feedback loops. To generate duty used for differential mode feedback loop, this paper propose relative sawtooth circuit using current divider circuit which makes ramp signal with variable dead-time. Two outputs of the Single-Inductor Dual-Output DC-DC Converter are specified for 2.8 V and 4.2 V with input voltage 2.5 V. The maximum conversion efficiency of designed SIDO DC-DC Converter is 95% at total output power of 539mW. Cross regulations of Boost1 and Boost2 are 3.57% and 4% each, when increasing twice times output current.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.520-523
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• 2016

This paper describes a DC-DC converter with MPPT control for thermoelectric energy harvesting. The designed circuit converts low voltage harvested from a thermoelectric generator into higher voltage for powering a load. A start-up circuit supplies VDD to a controller, and the controller turns on and off a NMOS switch of a main-boost converter. The converter supplies the boosted voltage to the load through the switch operation. Bulk-driven comparators can do the comparison under low voltage condition and are used for voltage regulation. Also, bulk-driven comparators raise system's efficiency. A peak conversion efficiency of 76% is achieved. The proposed circuit is designed in a 0.35um CMOS technology and its functionality has been verified through simulations. The designed chip occupies $933um{\times}769um$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.667-670
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• 2010

In this paper, a high voltage current sensing circuit for boost converter is designed and verified by Cadence SPECTRE simulations. The current mirror pair, power and sensing metal-oxide semiconductor field effect transistors (MOSFETs) with size ratio of K, is used in our on-chip current sensing circuit. Very low drain voltages of the current mirror pair should be matched to give accurate current sensing, so a folded-cascode opamp with a PMOS input pair is used in our design. A high voltage high side lateral-diffused MOS transistor (LDMOST) switch is used between the current sensing circuit and power MOSFET to protect the current sensing circuit from the high output voltage. Simulation results using 0.35 ${\mu}m$ BCD process show that current sensing is accurate and the pulse frequency modulation (PFM) boost converter using the proposed current sensing circuit satisfies with the specifications.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.56-66
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• 2014

In this paper, the solar cell need the characteristic interpreting because the solar cell changes greatly according to the isolation, temperature and load in the photovoltaic development. Moreover, to get many energy in photovoltaic development need the position tracking of the sun according to the environment change and it is necessary to control the output of solar cells up to the time. Simulation and composed microprocessor and sensor chip an power conversion system with boost converter to experiment results are performed to prove the analysis of the converter operation, and to show the possibility of energy harvesting and photovoltaic development need the position tracking small capacitance, the boost rate of boost converter was similar to 167 percent.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.194-196
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• 2009

본 논문은 연료전지용 전력변환 시스템 중 저주파(60Hz) 변압기를 사용하는 방식 인 Boost PCS를 대상으로 이전 연구에 진행되었던 최적설계를 바탕으로 제작된 PCS의 손실을 분석하고 컨버터부 인버터부 변압기부의 전력에 따른 효율을 분석하여 가정용 연료전지 PCS의 설계에서의 최적화 지침을 제공하고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.8
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• pp.423-429
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• 2006

Recently, the high frequency isolated boost DC/DC converter has been widely used for the PCS (Power Conditioning System) system because of its small size and low cost. However, the high frequency isolated boost DC/DC converters applied the conventional voltage-fed converter and current-fed converter have the problems such as the high conduction losses and the surge voltage due to the high circulating current and the leakage inductance, respectively. To overcome this problems, in this paper the secondary LLC resonant converter is proposed, and the experimental results of the secondary LLC series resonant converter for boost DC/DC converter are verified on the simulation based on the theoretical analysis and the 700W experimental prototype.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.3
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• pp.141-146
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• 2001

This paper presents a one digital controller two topology PWM DC-DC converter that controls, simultaneously, the separate Buck converter and boost converter with the different specification by using an inexpensive and efficient 8 bit micro-controller. One timer interrupt is used for the detection of output feedback voltage, and other two timer interrupts are used for the generation of PWM waveform for Buck and Boost converter. The control characteristics of one digital controller two topology PWM DC-DC converter is validated by experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.510-516
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• 1999

In this paper, a new high-powerfactor control method for boost-type rectifier is proposed, which removes the necessity of input current sensing. This method generates a sinewave duty template only from the line voltage waveform and rectifier output, and reduces reactive power remarkably utilizing three compensation coefficients which are determined through experiments. These compensations make the input current to be in phase with the input voltage all over the load range. A prototype boost-type rectifier is designed and experimental results are presented.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.115-117
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• 2009

본 논문은 단일 디지털 제어기를 이용하여 독립형 태양광 발진 시스템에 사용되는 태양전지에서 발생한 전력을 수집하고 필요에 따라 에너지 저장 장치에 전력을 저장하는 Boost 컨버터가 최대전력점에서 동작하도록 제어하면서, 이 전압을 부하에 필요한 전압 값으로 변환하는 Buck 컨버터를 동시에 제어하는 방법을 제안한다. 제안된 독립형 태양광 발전 시스템의 구성은 에너지를 발생하는 태양전지, 최대전력 점을 추종(MPPT)하도록 하는 Boost 컨버터, 부하에 적합한 준위의 전압을 공급하는 Buck 컨버터가 직렬로 연결되어 있다. 제안된 방법은 디지털 제어기의 제어변수 값들을 바꿈으로써 전체시스템의 출력특성을 쉽게 제어할 수 있어, 사용되는 태양전지 어레이의 종류와 환경조건 변화에 따라 쉽게 제어변수 값들을 조정할 수 있다. 또한 하나의 디지털 제어기로 최대전력점 제어부 및 Buck과 Boost 컨버터의 피드백 제어부를 구성하여 시스템의 구조가 간단해지기 때문에 소형 및 경량화를 이룰 수 있다.