• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.506-514
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• 1998

The design and fabrication of X-band(11.7~12 GHz) 2-stage monolithic microwave integrated circuit(MMIC) low noise amplifier (LNA) for active antenna are presented using $0.15{\mu}m\times140{\mu}m$ AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (P-HEMT). In each stage of the LNA, a series feedback by using a source inductor is used for both input matching and good stability. The measurement results are achieved as an input return loss under -17 dB, an output return loss under -15dB, a noise figure of 1.3dB, and a gain of 17 dB at X-band. This results almost concur with a design results except noise figure(NF). The chip size of the MMIC LNA is $1.43\times1.27$.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.4
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• pp.397-402
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• 2013

This paper proposes a new passive type LED driver which satisfies the standard of power factor (PF) and total harmonic distortion (THD). The proposed passive LED driver also has high-efficiency and long-life time characteristics compared to active LED driver which is composed of op-amp, switches and so on. By using just passive components such as inductor, capacitor, and diode, it has resolved extremely short-life time and low-efficiency problems of previous LED drivers. It has achieved PF of 0.99, THD of 16.4 %, and the total efficiency of 95 %. The proposed passive LED driver is fully analyzed and verified by simulations and experiments, which results are in good agreement each other.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.3
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• pp.285-293
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• 2004

In this Paper the electronic ballast using the SEPIC(Single Ended Primary Inductor Converter) converter for the multiple electrodeless fluorescent lamps is proposed, which has the structure of the active PFC and self oscillating function. The SEPIC converter system has the characteristics of the power factor with low input current harmonic distortion. The proposed control method is based on the aveage-current-mode using the dedicated integrated circuit UC3854. The proposed electronic ballast has the reduction effect for the energy and manufacturing cost because it is designed for tripple electrodeless fluorescent lamps. The experimental results shows that the power factor is higher and the THD is lower.

• Journal of Power Electronics
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• v.18 no.4
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• pp.965-974
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• 2018

A new zero-voltage-switching (ZVS) push-pull pulse-width modulation (PWM) converter is proposed in this paper. The wide ZVS condition for all of the switches is obtained by utilizing the energy stored in the output inductor and magnetizing inductance. As a result, the switching losses can be dramatically reduced. A simple auxiliary circuit including two small diodes and one capacitor is added at the secondary side of a high frequency (HF) transformer to reset the primary current during the circulating stage and to clamp the voltage spike across the rectifier diodes, which enables the use of low-voltage and low-cost diodes to reduce the conducting and reverse recovery losses. In addition, there are no active devices or resistors in the auxiliary circuit, which can be realized easily. A detailed steady operation analysis, characteristics, design considerations, experimental results and a loss breakdown are presented for the proposed converter. A 500 W prototype has been constructed to verify the effectiveness of the proposed concept.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.1
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• pp.28-35
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• 2007

This paper presents a high-speed flash analog-to-digital converter (ADC) for ultra wide band (UWB) receivers. In this flash ADC, the interpolating technique is adopted to reduce the number of the amplifiers and a linear and wide-bandwidth interpolating amplifier is presented. For this ADC, the transistor size for the cascaded stages is inversely scaled to improve the trade-off in bandwidth and power consumption. The active inductor peaking technique is also employed in the pre-amplifiers of comparators and the track-and-hold circuit to enhance the bandwidth. Furthermore, a digital-to-analog converter (DAC) is embedded for the sake of measurements. This chip has been fabricated in $0.13{\mu}m$ 1P8M CMOS process and the total power consumption is 113mW with 1V supply voltage. The ADC achieves 4-bit effective number of bits (ENOB) for input signal of 200MHz at 5-GSample/sec.

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.3
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• pp.9-16
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• 1972

In this article it is shown that a GIC circuit with conversion "s" can be realized and a inductor is realized as a RC active two terminal network by using it instead of a gyrator. It is also shown that arbitary stable transfer functions can be realized as the open-circuit voltage ratio of 2 port networks which include GIC;s. In relizing the GIC circuit using transistors, it is made clear that the nullatornorator model of atransistor can be successfully applied at least in the frequency range below 10kHz. The synthesis method using GIC's is characterized with the followings; First, arbitrary stable transfer functions are realized systematically by repeating very simple network structure. Second, in the overall network all circuit elements except GICs are only resistors. Third, the number of condensers in the overall network necessary for realizing the transfer function of n-th order are n, which is believed to be the least number expected. expected.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.4
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• pp.21-30
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• 2016

In a single-phase power factor correction (PFC), the standard cascaded control algorithm using a proportional-integral-derivative (PID) controller has two main drawbacks: an inability to track sinusoidal current reference and low harmonic compensation capability. These drawbacks cause poor power factor and high harmonics in grid current. To improve these drawbacks, this paper uses a proportional-integral-derivative-resonant (PIDR) controller which combines a type-III PID with proportional-resonant (PR) controllers in the PFC. Based on a small signal model of the PFC, the type-III PID controller was implemented taking into account the bandwidth and phase margin of the PFC system. To adopt the PR controllers, the spectrum of inductor current of the PFC was analyzed in frequency domain. The hybrid PIDR controller were simulated using PSCAD/EMTDC and implemented on a 3 kW PFC prototype hardware. The performance results of the hybrid PIDR controller were compared with those of an individual type-III PID controller. Both controllers were implemented successfully in the single-phase PFC. The total harmonic distortion of the proposed controller were much better than those of the individual type-III PID controller.

• Journal of IKEEE
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• v.20 no.3
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• pp.314-317
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• 2016

Recently, efforts to maximize battery life in progress with an increase in the demand for portable devices. In this paper, we propose multi-phase buck converter with fast transient response. Multi-phase buck converter may be used for the output capacitor of small size because the ripple cancellation effect, it is possible to use an inductor having an inductance less. The portable device for quick change from standby mode to active 4-phase design structure was given a fast transient response. The proposed multi-phase buck converter was fabricated using a 0.18 um CMOS process and the supply voltage ranges from 2.7V to 3.3V, the maximum load current is 500mA and settling time is 10us.

• Journal of Power Electronics
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• v.7 no.3
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• pp.246-256
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• 2007

In this paper, a novel type auxiliary active edge resonant snubber assisted zero current soft switching pulse modulation Single-Ended Push Pull (SEPP) series load resonant inverter using IGBT power modules is proposed for cost effective consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each switching mode's equivalent operating circuits. The new multi resonant high-frequency inverter with series load resonance and edge resonance can regulate its high frequency output power under a condition of a constant frequency zero current soft switching (ZCS) commutation principle on the basis of the asymmetrical pulse width modulation (PWM) control scheme. Brand-new consumer IH products using the proposed ZCS-PWM series load resonant SEPP high-frequency inverter using IGBTs is evaluated and discussed as compared with conventional high-frequency inverters on the basis of experimental results. In order to extend ZCS operation ranges under a low power setting PWM as well as to improve efficiency, the high frequency pulse density modulation (PDM) strategy is demonstrated for high frequency multi-resonant inverters. Its practical effectiveness is substantially proved from an application point of view.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.372-373
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• 2019

본 논문은 다중 권선 결합 인덕터를 이용한 능동 셀 밸런싱 회로의 밸런싱 속도를 향상시킬 수 있는 새로운 동작 모드를 제안한다. 다중 권선 결합 인덕터를 사용한 능동 셀 밸런싱 회로는 두 셀이 하나의 결합 인덕터 권선을 공유하며, 셀과 결합 인덕터 사이의 연결을 제어하기 위해 셀당 하나의 스위치가 사용된다. 이 회로는 비교적 높은 전압을 갖는 소스 셀에 저장된 에너지를 결합 인덕터에 저장한 뒤, 그 에너지를 목표 셀로 전달하는 방식으로 셀 밸런싱을 수행한다. 하지만, 회로 구조상서로 다른 권선을 공유하고, 동일한 위치에 연결된 셀 간 밸런싱을 수행할 경우, 두 번의 에너지 전달 과정을 통해 목표 셀로 에너지가 전달 되게 된다. 이는 에너지 전달 경로를 증가시키므로 회로의 효율과 셀 밸런싱 속도를 크게 저하시킨다. 본 논문은 위의 셀 조건에서 에너지 전달 경로를 단축시켜 셀 밸런싱 속도를 향상시킬 수 있는 새로운 동작 모드를 제안한다. 새로운 동작 모드 성능은 15W급 시작품을 이용하여 검증되었다.