• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.30 no.1
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• pp.25-32
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• 1994

An underwater speaker was made of a moving coil driver unite of usual speaker, acryl-boards, polyester resin, rubber and castor oil and it's frequency characteristics was measured in range of 250~600Hz in air water tank and sea. The results of measurements are follows: 1. Transmitting and receiving frequency of measurement frequency were similar in air, water tank and sea. 2. The input and output wave forms of a manufactured speaker which is not water-proof in air were similar to each other in 300~450Hz, but other frequencies showed distorted wave forms. 3. The input and output wave forms of an underwater speaker in water thank and sea were similar to each other in 250~600Hz. But output wave forms showed combination waves with very low frequency. 4. Transmitting and receiving frequency wave forms and resisting pressure of an underwater speaker at 80m in the depth of water were in good condition. Therefore it can be possible to use it as an underwater speaker.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.7
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• pp.474-480
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• 2003

We designed and tested a new scan driver output stage. Compared to conventional CMOS structured scan driver IC′s, the new NMOSFET-only scan driver circuit can reduce the chip area and therefore, the chip cost considerably. We confirmed the circuit operation with open drain power NMOSFET IC′s by driving 2"PDP test panel. We defined critical device parameters and their optimization methods lot the best circuit performance.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.164-165
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• 2001

An IGBT driver for serially connected pulse switching IGBTS was contructed and tested. The IGBT driver has ten output pulses with 1 ${\mu}ysec$ pulse width Its pulse repetition-rate can adjusted from 0 to 20 kHz. The output pulses was insulated from 10 kV high voltage by a pulse transformer. Their voltage amplitude are 18 V, voltage rising time 250 nsec., and voltage falling time 200 nsec when IGBT gates with 12 nF input capacitance are connected.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.409-412
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• 2006

A high data accuracy and low power consumption driving method and output stage of the source driver are proposed for the LTPS TFT-LCD in mobile applications. The proposed driving method is insensitive to the variations of the electrical characteristics of TFTs, which enables the output errors of the source driver are under 1/2 LSB in all gray levels. In addition, the power consumption of the driver with the method is decreased to 9.9mW which is 55.9% of that of the conventional source driver by reducing unnecessary charge waste.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.5
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• pp.976-981
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• 2009

This paper proposed optimal design and microcontroller driver for driving the thin-type ultrasonic motor. To find the optimal size of the stator, motions of the motor were simulated using ATILA by changing length, width and thickness of the ceramics. Two sinusoidal waves which have 90 degree phase difference were needed for driving the thin-type motor. The thin-type ultrasonic motor driver was composed of microcontroller(Atmega128), push-pull inverter, encoder and AD-converter. Microcontroller generates four square waves which have variable frequency and 25[%] duty ratio in $20{\sim}150$[kHz]. The output signals of microcontroller were converted to sine wave and cosine wave by push-pull inverter and were applied to the thin-type ultrasonic motor. The encoder and AD-converter were used for maintaining speed of the thin-type ultrasonic motor. The AD-converter controlled DC voltage of inverter in accordance with output signal of encoder. Using the driver, characteristics of the motor as speed and torque were measured.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.31-36
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• 2011

This paper investigates the ESD robustness of the stacked output driver with a 0.13um CMOS process. To represent an actual I/O system, we implemented stacked output driver circuits with pre-drivers and a rail-based power clamp. We implemented eight kinds of circuits varying pre-driver input connections and stacked driver size. The test circuits are examined with TLP measurements. It is shown that breakdown current and voltage can be increased by connecting the pre-driver input to a power supply and using stacked devices of a similar size. Based on the test results, design guideline is suggested to improve ESD robustness of the stacked output drivers.

• Journal of Power Electronics
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• v.18 no.2
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• pp.640-650
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• 2018

A TRIAC dimmable LED driver with a wide tuning range and a two-stage uniform dimming scheme is proposed in this paper. To solve the restricted dimming range problem caused by the limited conduction ratio of TRIAC dimmers, a conduction ratio compensation technique is introduced, which can increase the output current up to the rated output current when the TRIAC dimmer turns to the maximum conduction ratio. For further optimization, a two-stage uniform dimming diagram with a rapid dimming curve and a slow dimming curve is designed to make the LED driver regulated visually uniform in the whole adjustable range of the TRIAC dimmer. The proposed control chip is fabricated in a TSMC $0.35{\mu}m$ 5V/650V CMOS/LDMOS process, and verified on a 21V/500mA circuit prototype. The test results show that, in the 90V/60Hz~132V/60Hz ac input range, the voltage linear regulation is 2.6%, the power factor is 99.5% and the efficiency is 83%. Moreover, in the dimming mode, the dimming rate is less than 1% when the maximum dimming current is 516mA and the minimum dimming current is only about 5mA.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.138-139
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• 2017

This paper describes the design and implementation of a trigger circuit which can be series connected with main pulse circuit for a xenon flash lamp driver. For generating high voltage, the trigger circuit is designed as an inductive energy storage pulsed power modulator with 2 state step-up circuit consisting of a boost converter and a flyback circuit. In order to guarantee pulse width, a resonant capacitor on the output side of the flyback circuit is designed. This capacitor limits the output voltage to protect the flyback switch. In addition, to protect another power supply of xenon flash lamp driver from trigger pulse, the high voltage transformer which can carry the full current of main pulse is designed. To verify the proposed design, the trigger circuit is developed with the specification of maximum 23 kV, 0.6 J/pulse output and tested with a xenon flash lamp driver consisting of a main pulse circuit and a simmer circuit.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.967_968
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• 2009

For lighting application, high-power LED nowadays is driven at 350mA and a sensing resistor is used to provide feedback for LED-current regulation. This method adds an IR drop at the output branch, and limits power efficiency as LED current is large and keeps increasing. In this paper, a power efficient LED-current sensing circuit is proposed. The circuit does not use any sensing resistor but extracts LED-current information from the output capacitor of the driver. Controlling the brightness of LEDs requires a driver that provides a constant, regulated current. In one case, the converter may need to step down the input voltage, and, in another, it may need to boost up the output voltage. These situations often arise in applications with wide-ranging ""dirty"" input power sources, such as automotive systems. And, the driver topology must be able to generate a large enough output voltage to forward bias the LEDs. So, to provide this requirements, 13W prototype Buck-Boost Converter is used.

• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.59-61
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• 2017

This research was analyzed thermal characteristics that was appointed disadvantage when smart LED driver ICs was packaged and we applied extracted thermal characteristics for optimal layout design. We confirmed reliability of smart LED driver ICs package without additional heat sink. If the package is not heat sink, we are possible to minimize package. For extracting thermal loss due to overshoot current, we increased driver current by two and three times. As a result of experiment, we obtained 22 mW and 49.5 mW thermal loss. And we obtained optimal data of 350 mA driver current. It is important to distance between power MOSFET and driver ICs. If the distance was increased, the temperature of package was decreased. And so we obtained optimal data of 3.7 mm distance between power MOSFET and driver ICs. Finally, we fabricated real package and we analyzed the electrical characteristics. We obtained constant 35 V output voltage and 80% efficiency.