• Journal of IKEEE
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• v.13 no.2
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• pp.208-215
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• 2009

The high efficiency power management IC(PMIC) with DT-CMOS(Dynamic Threshold voltage MOSFET) switching device for portable application is proposed in this paper. Because portable applications need high output voltages and low output voltage, Boost converter and Buck converter are embedded in One-chip. PMIC is controlled with PWM control method in order to have high power efficiency at high current level. DTMOS with low on-resistance is designed to decrease conduction loss. Boost converter and Buck converter, are based on Voltage-mode PWM control circuits and low on-resistance switching device, achieved the high efficiency near 92.1% and 95%, respectively, at 100mA output current. And Step-down DC-DC converter in stand-by mode below 1mA is designed with LDO in order to achive high efficiency.

• Journal of IKEEE
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• v.17 no.3
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• pp.284-293
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• 2013

This paper describes a DC-DC boost converter for thermoelectric energy harvesting. The designed converter boosts the VDD through a start-up block from a low-output voltage of a thermoelectric device and the boosted VDD is used to operate the internal control block. When the VDD reaches a predefined value, a detector circuit makes the start-up block turn off to minimize current consumption. The final boosted VOUT is achieved by alternately operating the DC-DC converter for VDD and the main DC-DC converter for VOUT according to the comparator outputs. Simulation results shows that the designed converter generates 2.65V from an input voltage of 200mV and its maximum power efficiency is 63%. The area of the chip designed using a 0.35um CMOS process is $1.3mm{\times}0.7mm$ including pads.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.599-600
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• 2008

This paper presents a high performance DC-DC boost converter by current-mode control method. As load current change, the converter change PWM/PFM operation automatically. current-mode DC-DC boost converter is implemented in a standard $0.35{\mu}m$ CMOS process. The peak efficiency was 94 % with a switching frequency of 1.2MHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.749-753
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• 2003

This paper presents an output voltage regulation system using PWM Buck-Boost AC-AC converter for power qualify improvement of custom power. This paper proposes dynamic modeling of the system for control object and in addition, a controller design example. Therefore, system state equation is derived whereby the transfer function could be obtained. The paper shows a regulation controller for tracking the output voltage to the reference under specific operating point. Finally, this paper shows validity and practical applicability of the proposed modelling and system design by experimental results.

• Journal of IKEEE
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• v.20 no.1
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• pp.45-53
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• 2016

This paper presents a CMOS interface circuit for vibration energy harvesting with MPPT (Maximum Power Point Tracking). In the proposed system a PMU (Power Management Unit) is employed at the output of a DC-DC boost converter to provide a regulated output with low-cost and simple architecture. In addition an MPPT controller using FOC (Fractional Open Circuit) technique is designed to harvest maximum power from vibration devices and increase efficiency of overall system. The AC signal from vibration devices is converted into a DC signal by an AC-DC converter, and then boosted through the DC-DC boost converter. The boosted signal is converted into a duty-cycled and regulated signal and delivered to loads by the PMU. A full-wave rectifier using active diodes is used as the AC-DC converter for high efficiency, and a DC-DC boost converter architecture using a schottky diode is employed for a simple control circuitry. The proposed circuit has been designed in a 0.35um CMOS process, and the designed chip occupies $915{\mu}m{\times}895{\mu}m$. Simulation results shows that the maximum power efficiency of the entire system is 83.4%.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.100-101
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• 2017

This paper presents the dynamics of the current-mode controlled buck and boost converters, which are both connected to an ill-conditioned source. This paper investigates the origin of potential instability and demonstrates internal/external dynamics of the converters under adverse interactions with the source.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.84-86
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• 2009

Isolated boost converter is desirable in the dc/dc converter applications where isolation is required and a large step up is needed. In this paper, it is proposed and analyzed the isolated boost converter which can step up low input voltage to high output voltage using transformer. Instead of using a conventional scheme, the proposed converter has the reset winding for volt-sec balance of transformer. Finally, the validity of the proposed isolated boost converter is verified by simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.3
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• pp.31-39
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• 2012

This paper presents a high efficiency coupled inductor boost DC-DC converter that uses a simple clamp circuit and the coupled inductor and thus overcomes output voltage limit of the conventional boost converter. The proposed converter solves problems of voltage stress of the power semiconductor switch and reverse recovery of the output diode using a simple clamp circuit composed of a diode and a capacitor, and thus the converter improves its total efficiency. In this paper, the operational principle of the proposed converter is explained by each mode and then a design example for the prototype converter based on the explanation is shown. And good performance of the proposed converter is verified through experimental results of the prototype converter that is implemented with the designed circuit parameters.

• Journal of IKEEE
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• v.23 no.3
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• pp.1061-1067
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• 2019

In this paper, a highly integrated 3-channel DC-DC converter is designed using power transistor width scaling (PTWS). For positive voltage, $V_{POS}$, a boost converter is designed using the set-time variable pulse width modultaion (SPWM) dual-mode and PTWS to improve efficiency at light load. For negative voltage, $V_{NEG}$, a 0.5 x regulated inverting charge pump is designed with pulse skipping modulation (PSM) controller to reduce power consumption, and for an additional positive voltage, $V_{AVDD}$, a LDO circuit is designed. The proposed DC-DC converter has been designed using a $0.18{\mu}m$ BCDMOS process. Simulation results show that the proposed converter has power efficiency of 56%~90% for load current range of 1 mA~70 mA and output ripple voltage less than 5 mV at positive voltage.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.209-211
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• 2009

본 논문에서는 고효율 DC-DC 컨버터와 인버터에 의한 연료전지발전용 전력변환기를 제안한다. 제안하는 전력변환기는 Boost Converter와 LLC공진 컨버터의 2 stage 조합으로 구성되어 있다. 제안하는 전력변환기의 동작을 분석하기 위해 PSCAD/EMTDC를 이용하여 연료전지의 출력 동특성을 나타내는 모델과 제안하는 전력변환기의 모델을 개발하였다. 시뮬레이션모델의 검증을 위해 하드웨어장치를 구성하여 실험을 실시하였다. 제안하는 전력변환기는 정격출력에서 저전압특성을 갖는 연료전지를 전력계통에 고효율로 연계하는데 유용할 것으로 보인다.