• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.4
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• pp.42-50
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• 2003

This paper presents an embedded RC oscillator which has temperature compensation circuits. The conventional RC oscillator has frequency deviation about 15%, which is caused by variation of resistors and the reference voltage of schmitt trigger from the temperature condition. In this paper, the proposed circuit use a CMOS bandgap reference having balanced current temperature coefficients as a triggering voltage of schmitt trigger. The constant current sources consist of current mirror circuit with the positive and negative temperature coefficient. The proposed circuit shows less 3% frequency deviation for variation of temperature, supply voltage and process parameters.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.139-140
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• 2016

이 논문에서는, 홀드-업 보상 기법을 통해 넓은 입력 범위에서 최적 설계가 가능한 비대칭 하프-브리지 컨버터를 제안한다. 제안된 회로가 갖는 주된 장점은 기존의 회로 동작에 어떠한 변화도 주지 않은 채, 넓은 입력 전압 범위에서도 최적 설계가 가능하게 하는 것이다. 기존의 비대칭 하프-브리지 컨버터는 입력 전압이 가장 낮은 홀드-업 시 설계가 되어, 정상 동작 시 비대칭 동작에 의한 단점을 갖는 반면, 제안 된 컨버터는 홀드-업 시 추가적인 전압 이득을 통해 출력 전압을 제어하기 때문에 홀드-업 동작 시 넓은 입력 전압 범위에 관계없이 컨버터의 최적 설계가 가능하다. 또한 기존의 방법들에 비해, 정상 동작 시에 추가 소자에 의한 손실이 발생하지 않아, 전 범위에서 고효율을 달성하였다. 250-410V 입력, 45V/3.3A 출력의 컨버터를 통해 제안 된 회로의 동작을 검증하였다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.175-178
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• 2000

본 연구에서는 CDMA단말기용 Receiver MMIC를 설계하였다. 전체회로는 저잡음 증폭기, 하향 주파수 혼합기 그리고 중간주파수 증폭기로 구성된다. 또한 문턱전압과 전원전압의 변화에 대해 회로의 안정성을 높이는 바이어스 보상회로를 추가하였다. 설계시 높은 선형성과 저잡음 특성을 가지도록 토폴리기를 구성하였고 설계 결과 전체 이득은 28.5dB, 저잡음 증폭기의 입력IP3는 8dBm, 하향주파수 혼합기의 입력 IP3는 0dBm이며 전체회로의 소모전류는 22.1mA이다. 레이아웃된 전체회로의 크기는 1.4$\times$1.4 [$\textrm{mm}^2$] 이다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.200-201
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• 2017

무선전력전송 시스템의 전력 수신부는 많은 경우 송신부에 비해 크기가 작으므로 자계결합 에너지링크 코일의 권선을 비대칭으로 설계할 필요가 있다. 본 논문은 직렬 공진 보상 구조의 자계결합 무선전력전송에서 에너지링크 전압이득과 전력전송효율을 동시에 고려해 전력변환회로 관점에서의 비대칭 코일의 도식적인 분석 및 설계 방법을 제안한다. 제안하는 설계평면을 통해 에너지링크 코일의 정렬이 어긋날 때 혹은 부하요구가 변할 때 에너지링크의 전압이득과 전력전송효율 변화를 직관적으로 예측할 수 있으며 주어진 설계조건에 따라 에너지 링크를 간단히 설계할 수 있다. 본 제안방법은 회로 시뮬레이션을 통해 검증 되었다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.3
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• pp.205-210
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• 2022

A novel OLED pixel circuit is proposed in this paper that uses only n-type thin-film transistors(TFTs) to improve the luminance non-uniformity of the AMOLED display caused by the threshold voltage variation of an OLED driving TFT. The proposed OLED pixel circuit is composed of 6 n-channel TFTs and 2 capacitors. The operation of the proposed OLED pixel circuit consists of the capacitor initializing period, threshold voltage sensing period of an OLED·driving TFT, image data voltage writing period, and OLED·emitting period. As a result of SmartSpice simulation, when the threshold voltage of·OLED·driving TFT varies from 1.2 V to 1.8 V, the proposed OLED pixel circuit has a maximum current error of 5.18 % at IOLED = 1 nA. And, when the OLED cathode voltage rises by 0.1 V, the proposed OLED pixel circuit has very little change in the OLED current compared to the conventional OLED pixel circuit. Therefore, the proposed pixel circuit exhibits superior compensation characteristics for the threshold voltage variation of an OLED driving TFT and the rise of the OLED cathode voltage compared to the conventional OLED pixel circuit.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.10
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• pp.1-8
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• 2009

In this paper, a temperature variation-insensitive power-up detector for use in analog and digital integrated systems has been proposed. To provide temperature-insensitive characteristic, nMOS and pMOS voltage dividers in the proposed power-up detector are made to have zero temperature coefficient by exploiting the fact that the effective gate-source voltage of a MOS transistor can result in mutual compensation of mobility and threshold voltage for temperature independency. Comparison results using a 68-nm CMOS process indicate that the proposed power-up detector achieves as small as 4 mV voltage variation at 1.0 V power-up voltage over a temperature range of $-30^{\circ}C$ to $90^{\circ}C$, resulting in 92.6% reduction on power-up voltage variations over conventional power-up detectors.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.4
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• pp.43-49
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• 2010

Power capacitor has been used to compensate for the low power factor of inductive load and to reduce harmonics generated by the power conversion device with reactor. The increase of voltage and current and thermal generation are extremely hard on the life of condenser. Current will be increased, provided that voltage and frequency of condenser increase also. The increase of voltage and frequency justly extends thermal generation. Both act on insulation stress and can afford to premature fault In this paper, we measured thermal distribution of condenser with infrared rays camera in case of variance of voltage and frequency. We were assured that the increase of voltage and frequency produces high heat and exceedingly shortens the life of condenser.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.6
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• pp.517-523
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• 2002

A sensorless control of a PM synchronous motor with the compensation of the motor parameter variation is presented. The rotor position is estimated by using the d-axis and q-axis current errors between the real system and motor model of the position estimator. The stator resistance is measured at low speeds when the motor changes its rotating direction and the variation of the stator resistance and back emf constant caused by the temperature variation is compensated. The gains in the position estimator are also adapted according to the motor speeds.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.21-28
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• 2009

Power capacitor has been used to compensate for the low power factor of inductive load and to reduce harmonics generated by the power conversion device with reactor. Power quality is mainly referred to the voltage quality and it is very important for the stable operation of load. But if voltage rms is temporary changed, it acts on capacitor as an electrical stress. In this paper, we analyzed that capacitor can be given by voltage, current and capacity's variance under the sag and swell condition. If reactor is connected at capacitor, sag can be aside from the question. But it can act an amount of stress on capacitor in the swell region.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.544-552
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• 2004

This paper deals with the hybrid active filter which can reduce the 11th/13th harmonics in AC network by using the single tuned filter. Since the proposed algorithm uses the detuning compensation capability of the filter, the output voltage of the proposed active power filter is changed according to the capacitance of capacitors, magnitude of harmonic current, resonance frequency and control mode. In this paper, the control characteristics and the design of hybrid active filter is investigated. A new hybrid active filter with new algorithm, which is an active filter with single tuned filter instead of double tuned filter, is proposed.