• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.116-121
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• 2012

DC/DC switching power converters produce DC output voltages from different DC input sources. The converter is used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The DC/DC converter is composed of a PWM-IC (pulse width modulation integrated circuit) controller, a MOSFET (metal-oxide semi-conductor field-effect transistor), an inductor, capacitors, and resistors, etc. PWM is applied to control and regulate the total output voltage. In this paper, radiation shows the main influence on the changes in the electrical characteristics of comparator, operational amplifier, etc. in PWM-IC. In the PWM-IC operation, the missing pulses, the changes in pulse width, and the changes of the output waveform are studied by the simulation program with integrated circuit emphasis (SPICE) and compared with experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.79-84
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• 2013

DC/DC switching power converters are commonly used to generate a regulated DC output voltage with high efficiency. The DC/DC converter is composed of a PWM-IC (pulse width modulation-integrated circuit) controller, a MOSFET (metal-oxide semiconductor field effect transistor), inductor, capacitor, etc. It is shown that the variation of threshold voltage and the offset voltage in the electrical characteristics of PWM-IC increase by radiation effects in TID (Total Ionizing Dose) testing at the low energy ${\gamma}$ rays using $^{60}Co$, and 4 heavy ions applied for SEL (Single Event Latch-up) make the PWM pulse unstable. Also, the output waveform for the given input in the DC/DC converter is observed by the simulation program with integrated circuit emphasis (SPICE). TID testing on PWM-IC is accomplished up to the total dose of 30 krad, and the cross section($cm^2$) versus LET($MeV/mg/cm^2$) in the PWM operation is studied at SEL testing after implementation of the controller board.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.702-708
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• 2020

Recently, as LED display systems have become larger, research on effective power control methods for the systems has been in progress. This paper proposes a power control method to minimize power loss due to the difference in LED characteristics for each channel of a backlight unit (BLU) system. The proposed LED driver IC has a power optimization function and detects the minimum headroom voltage for constant current operation of all channels and linearly controls the DC-DC converter output. Thus, it minimizes power consumption due to unnecessary additional voltage. In addition, it does not require a voltage sensing comparator or a voltage generation circuit for each channel. This has a great advantage in reducing the chip size and for stabilization when implementing an integrated circuit. In order to verify the proposed function, an IC was designed using Cadence and Synopsys' design tools, and it was fabricated with a Magnachip 0.35um 5V/40V CMOS process. The experiments confirmed that the proposed power control method controls the minimum required voltage of the BLU system.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2577-2579
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• 2002

In this paper, we describe a CMOS DC-DC converter with a variable output voltage(8-12V @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 a 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 0.6${\mu}m$ 2-poly, 3-metal CMOS process and could be applied to the Personal Digital Assistants(PDA), Cellular Phone, Laptop Computer, etc.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.7
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• pp.756-759
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• 2014

DC/DC converters are commonly used to generate regulated DC output voltages with high-power efficiencies from different DC input sources. The converters can be applied in the regenerative braking of DC motors to return energy back to the supply, resulting in energy savings for the systems at periodic intervals. The fundamental converter studied here consists of an IGBT (Insulated Gate Bipolar mode Transistor), an inductor, a capacitor, a diode, a PWM-IC (Pulse Width Modulation Integrated Circuit) controller with oscillator, amplifier, and comparator. The PWM-IC is a core element and delivers the switching waveform to the gate of the IGBT in a stable manner. Display of the DC/DC converter output depends on the IGBT's changes in the threshold voltage and PWM-IC's pulse width. The simulation was conducted by PSIM software, and the hardware of the DC/DC converter was also implemented. It is necessary to study the fact that the output voltage depends on the duty rate of D, and to compare the output of experimental result with the theory and the simulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.138-143
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• 2003

A double spiral thin-film inductor with a NiFe magnetic core is integrated with DC-DC converter IC. The NiFe core is deposited on a polyimide film as the thinckness of NiFe is 2.5~3.5 ${\mu}$m. Then, copper conductor line is deposited on the NiFe core with double spiral structure. Process integration is performed by sequential processes of etching the polyimide film deposited both top and bottom of the NiFe core and electroplation copper conductor line from exposed metal pad of the DC-DC converter IC. Process integration is simplified by elimination planarization process for top core because the proposed thin-film inductor has a bottom NiFe core only. Inductor of the fabricated monolithic DC-DC converter IC is 0.53 ${\mu}$H when the area of converter IC and thin-film inductor are 5X5$\textrm{mm}^2$ and 3.5X2.5$\textrm{mm}^2$, respectively. The efficiency is 72% when input voltage and output voltage are 3.5 V and 6 V, respectively at the operation frequency of 8 MHz.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.321-324
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• 2004

This paper presents a package IC containing some components of DC/DC converter block for mobile phone's sub OLED(Organic Light Emitting Display). Package IC contains a load switch, a control IC, a diode, a switch for on/off operation, and a switch for changing output voltage. It operates with switching frequency of 100kHz, within the range of input voltage, $3.2V\~5.5V$. Duty ratio can be changed up to $93\%$, and maximum power efficiency is $85\%$. This package IC is loaded onto three model of 1.2W mobile phone's sub-OLED.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.28-31
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• 2008

22.9kV 50MVA HTS power cable has been developed and tested by Korea Electrotechnology Research Institute and LS Cable Company and it was supported by a grant from Center for Applied Superconductivity Technology of the 21st Century Frontier R&D Program. In this paper, DC Ic of 100m HTS cable which is installed at Kochang testing station was measured and analyzed. A measurement technique of DC Ic used by resistance and inductance removal method is established.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.367-369
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• 2008

본 논문은 중용량에 적합한 새로운 이중출력 LLC 공진형 DC/DC 컨버터에 관한 것으로써, 별도의 Post-regulator및 추가되는 제어 IC 없이 정밀한 이중출력이 가능한 새로운 방식의 컨버터를 제안한다. 제안된 컨버터의 제어방식은 펄스폭 변조(PWM)와 동시에 주파수 변조(PFM)를 통해 이루어지며 Master 와 Slave 출력을 각각 주파수, 듀티로 제어함으로써 Slave 출력을 위한 별도의 Post-Regulator 및 제어 IC가 필요 없기 때문에, 저가의 컨버터 구현이 가능하다. 또한 기존 LLC 공진형 DC/DC 컨버터와 같이 스위칭 소자의 영전압 스위칭이 보장되는 동시에, Post-Regulator 로 인한 손실이 없기 때문에 효율 및 발열 특성이 매우 우수하다. 본 논문에서는 제안된 컨버터의 우수성과 신뢰성 검증을 위해, 실제로 50" FHD급 PDP용 전원회로를 위한 시작품을 제작하고 이를 이용한 실험결과를 바탕으로 제안된 컨버터의 타당성을 검증한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.453-460
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• 2008

This paper proposes a new multi-output LLC resonant converter by using single control IC, which has the tight-regulated dual output voltage without additional power devices and controller. The proposed converter has master and slave outputs, of which regulations are achieved by the PWM(pulse width modulation) and PFM(pulse frequency modulation), respectively. Different from the conventional dual-output LLC resonant converter, the proposed converter has no additional post-regulators like a boost converter. Therefore, it features a low cost, small size, and high efficiency. To confirm the validity and prove the superiority of proposed converter, simulated and experimental results on a 50" FHD PDP power set prototype are presented.