• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.267-270
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• 2014

This paper presents a CMOS interface circuit for vibration energy harvesting. The proposed circuit consists of an AC-DC converter and a DC-DC boost converter. The AC-DC converter rectifies the AC signals from vibration devices(PZT), and the DC-DC boost converter generates a boosted and regulated output at a predefined level. A full-wave rectifier using active diodes is used as the AC-DC converter for high efficiency, and a schottky diode type DC-DC boost converter is used for a simple control circuitry. A MPPT(Maximum Power Point Tracking) control is also employed to harvest the maximum power from the PZT. The proposed circuit has been designed in a 0.35um CMOS process. The chip area is $530um{\times}325um$. Simulation results shows that the maximum efficiencies of the AC-DC converter and DC-DC boost converter are 97.7% and 89.2%, respectively. The maximum efficiency of the entire system is 87.2%.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.891-894
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• 2003

본 논문에서는 3-상 클럭을 이용하여 UP/DOWN 변환을 동시에 수행하는 DC/DC 변환기의 설계에 대해 설명한다. 기존의 UP/DOWN DC/DC 변환기의 경우에는 한 스텝당 변화하는 전압의 양이 많아서 출력에 수십 mV의 리플이 존재하게 된다. 이 리플을 줄이기 위해서는 L, C의 값을 크게 해 주어야하는 문제가 있다. 그러나, 설계된 UP/DOWN DC/DC 변환기는 기존의 UP/DOWN DC/DC 변환기의 구조를 가지면서, 3-상 클럭을 이용하여 한 스텝당 변화하는 전압의 양을 작게 하여 작은 L, C의 값을 가지고도 4mV이하의 출력 리플을 갖는 안정된 전압 변환을 하도록 설계하였다. 설계된 변환기는 0.25㎛ standard CMOS 공정을 이용하여 구현하였다. 구현 된 칩의 면적은 1.8 mm × 0.8 mm이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.412-415
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• 2015

This paper presents a MPPT(Maximum Power Point Tracking) control CMOS interface circuit for vibration energy harvesting. The proposed circuit consists of an AC-DC converter, MPPT Controller, DC-DC boost converter and PMU(Power Management Unit). The AC-DC converter rectifies the AC signals from vibration devices(PZT). MPPT controller is employed to harvest the maximum power from the PZT and increase efficiency of overall system. The DC-DC boost converter generates a boosted and regulated output at a predefined level and provides energy to load using PMU. A full-wave rectifier using active diodes is used as the AC-DC converter for high efficiency, and a schottky diode type DC-DC boost converter is used for a simple control circuitry. The proposed circuit has been designed in a 0.35um CMOS process. The chip area is $950um{\times}920um$.

• The Magazine of the IEIE
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• v.37 no.8
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• pp.86-94
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• 2010

본 논문에서는 전류 제어 방식을 갖는 DC-DC 변환기에 사용되는 기울기 보상회로에 있어서 가변적으로 동작하는 기울기 보상회로를 제안하였다. 시비율이 50% 이상으로 동작하는 DC-DC 변환기의 시스템의 안정도를 유지하기 위해서는, 램프 기울기 보상회로가 반드시 필요하다. 고정적인 기울기의 보상은 동작 범위를 제한하게 된다. 제안된 가변 기울기 보상회로는 넓은 범위의 입력 전압과 출력 전압에 적합하도록 설계 되었으며, LED 드라이버 응용분야에 적용하기 위한 DC-DC 변환기에 사용되었다. 동작을 검증하기 위하여, 0.35-um BDC 공정으로 회로를 제작하여 측정하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.31-40
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• 2009

This paper presents a design of a high performance DC-DC boost converter as a power module for SOC designs. It applied to this chip that reduced inductor and capacitor for integrating on a chip, and it operates with a switching frequency of 100MHz. It has reliability and stability in high switching frequency. The controller of DC-DC boost converter is designed by voltage-mode control method and compensated properly. The designed DC-DC converter is fabricated with the 0.18${\mu}m$ standard CMOS technology with a thick-gate oxide option. The overall die size is 8.14$mm^2$, and controller size is 1.15$mm^2$. The converter has the maximum efficiency over 76% for the output voltage of 4V and load current larger 300mA. The load regulation is 0.012% (0.5mV) for the load current change of 100mA.

• 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.

• 전자공학회논문지 IE
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• v.47 no.3
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• pp.14-18
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• 2010

In this paper, we describe a CMOS DC-DC converter with a variable output voltage(5-7V @100mA) for a portable battery-operated system applications. The proposed DC-DC converter is used along with a Pulse-Frequency Modulation (PFM) method and consists of reference circuit, a feedback resistor, a controller, and an internal oscillator. The integrated DC-DC converter with two external passive components(L,C) has been designed and fabricated on a 0.5um 2-poly 3-metal CMOS process and could be applied to the Personal Digital Assistants(PDA), cellular Phone, Laptop Computer, etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.404-407
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• 2011

This paper presents a design of current mode PWM/PFM DC-DC Boost converter. This DC-DC Boost Converter operates with PWM mode at the heavy loads and with PFM mode at light loads. The DC-DC boost converter is designed with CMOS 0.35${\mu}m$ technology. It operates at 500KHz and can drive a load current up to 600mA. It has a maximum power efficiency of 92.1%. The total chip area is $1300{\mu}m{\times}1070{\mu}m$ including pads. The DC-DC boost converter operates in a wide range of load currents while occupying a small chip area.

• Journal of IKEEE
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• v.16 no.3
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• pp.203-210
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• 2012

Since the non-overlapping gate driver used in conventional DC-DC boost converters generates fixed dead-times, the converters suffer from the body-diode conduction loss or the charge-sharing loss. To reduce the efficiency degradation due to these losses, this paper presents a PWM DC-DC boost converter with adaptive dead-time control. The proposed DC-DC boost converter delivering 3.3V output from a 2.5V input is designed with CMOS $0.3{\mu}m$ technology. It operates at 500kHz and has a maximum power efficiency of 97.3%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.247-250
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• 2012

This paper describes a DC-DC Boost converter for Thermoelectric Energy Harvesting. The designed converter boosts the $V_{DD}$ through a start-up block from a low output voltage of thermoelectric devices and the boosted $V_{DD}$ is used to operate the internal block circuits. When $V_{DD}$ reaches a predefined value, a detector circuit makes the start-up block turn off for minimizing current consumption. The final boosted $V_{OUT}$ is achieved by alternately operating the DC-DC converter for $V_{DD}$ and the other converter for final output $V_{OUT}$ according to the comparator output. Simulation results shows that the designed converter outputs 2.8V from an input voltage of 200mV. The area of the chip designed using a 0.35um CMOS process is $1.52mm{\times}0.95mm$ including pads.