• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.84-85
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• 2008

In this paper, differential cross coupled LC VCOs with two noise frequency filtering techniques are proposed. Both VCOs are based on symmetric capacitor with asymmetric inductor tank structure. The VCO using low pass filtering technique shows low phase noise of -130.40 dBc/Hz at 1 MHz offset when the center frequency is 1.619 GHz. And the other VCO using band pass filtering technique shows -127.93 dBc/Hz at 1 MHz offset frequency when center frequency is 1.604 GHz. Two noise frequency filtering techniques are approached with different target.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.181-182
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• 2015

본 논문에서는 태양전지, 연료전지 등 저전압 에너지원 응용에 적합한 고승압 컨버터를 제안한다. 제안하는 토폴로지는 부스트 컨버터를 기반으로 LC 병렬 공진 탱크를 이용함으로써 높은 승압비를 얻을 수 있다. 추가된 스위치와 다이오드는 각각 영전압 스위칭 턴 온과 영전류 스위칭 턴 오프의 특성을 갖는다. 250W(380V, 0.658A)의 시작품을 제작하여 제안하는 회로의 타당성을 검증하였다

• Journal of electromagnetic engineering and science
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• v.9 no.2
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• pp.98-104
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• 2009

An InGaP/GaAs MMIC LC VCO designed with Harmonic Noise Frequency Filtering(HNFF) technique is presented. In this VCO, internal inductance is found to lower the phase noise, based on an analytic understanding of phase noise. This VCO directly drives the on-chip double balanced mixer to convert RF carrier to IF frequency through local oscillator. Furthermore, final power performance is improved by output amplifier. This paper presents the design for a 1.721 GHz enhanced LC VCO, high power double balance mixer, and output amplifier that have been designed to optimize low phase noise and high output power. The presented asymmetric inductance tank(AIT) VCO exhibited a phase noise of -133.96 dBc/Hz at 1 MHz offset and a tuning range from 1.46 GHz to 1.721 GHz. In measurement, on-chip down-converter shows a third-order input intercept point(IIP3) of 12.55 dBm, a third-order output intercept point(OIP3) of 21.45 dBm, an RF return loss of -31 dB, and an IF return loss of -26 dB. The RF-IF isolation is -57 dB. Also, a conversion gain is 8.9 dB through output amplifier. The total on-chip down-converter is implanted in 2.56${\times}$1.07 mm$^2$ of chip area.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.155-159
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• 2003

This paper presents fully integrated 5 GHz band low phase noise LC tank VCO. The implemented VCO is tuned by integrated PN diode and tuning rage is $5.01{\sim}5.30$ GHz under $0{\sim}3 V$ control voltage. For good phase noise performance, LC filtering technique, common in Si CMOS process, is used, and to prevent degradation of phase noise performance by collector shot-noise and to reduce power dissipation the HBT is biased at low collector current density bias point. The measured phase noise is -87.8 dBc/Hz at 100 kHz offset frequency and -111.4 dBc/Hz at 1 MHz offset frequency which is good performance. Moreover phase noise is improved by roughly 5 dEc by LC filter. It is the first experimental result in InGaP/GaAs HBT process. The figure of merit of the fabricated VCO with LC filter is -172.1 dBc/Hz. It is the best result among 5 GHz InGaP HBT VCOs. Moreover this work shows lower DC power consumption, higher output power and more fixed output power compared with previous 4, 5 GHz band InGaP HBT VCOs.

• Journal of Power System Engineering
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• v.9 no.1
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• pp.50-56
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• 2005

The corrosion experiment was performed for 120 hours on the specimens in the natural seawater tank with four steps of the loaded torsional stress. The surface corrosion pattern of SCM440 area was showed global corrosion and narrow pitting, that was cause by galvanic corrosion between friction welded IN713LC and SCM440. But corrosion does not proceeded from IN713LC area. Initially, the average relative electrode potential and corrosion current were decreased suddenly, by and large, it was stabilized gradually tend to decreasing with the elapse of the immersion time. The corrosion rate was decreased by increasing the load stress, but 200 MPa specimen was showed most large value.

• Journal of Life Science
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• v.26 no.2
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• pp.181-189
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• 2016

The aim of this study was to identify the effects of dithiopyr (DTP), a herbicide, on behavior in zebrafish. The toxicity of DTP has rarely been investigated in fish. In the present study, zebrafish were exposed to different concentrations of DTP in the range of 10-20 μM for 48 h in a test container, in order to measure the value of median lethal concentrations (LC₅₀). Behavioral experiments were performed, including the novel tank test (NTT) and the open field test (OFT), to assess stress responses or locomotion. After exposure to the DTP solution at a sublethal concentration of 2.5–10 μM for 6 min, the behavior of the zebrafish was observed for 6 min. In the acute toxicity test, the LC₅₀ value of DTP showed as 14.49 μM in the zebrafish. The NTT showed that the duration of immobility and the velocity were significantly increased by exposure at a concentration of 5 μM of DTP, compared with a control group (p<0.05). However, compared with the control group, DTP significantly decreased the distance moved and the frequency at the top of the tank, and significantly increased the turn angle and duration at the bottom, in a concentration-dependent manner (p<0.05). In addition, in the OFT, exposure to DTP significantly decreased the distance moved and velocity compared with the control group (p<0.05). Exposure to DTP also significantly increased the duration of immobility, the turn angle, and the meandering movement, in a concentration-dependent manner (p<0.05). Further, exposure to DTP at a low concentration elevated whole-body cortisol levels in the zebrafish. The results of this study thus suggest that DTP induces a toxic response and negative effects on behavior and the endocrine system in zebrafish.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.237-239
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• 2009

This paper presents a new developed 160kV-120kW Class MPC (magnetic pulse compressor) power supply for DeNOx, DeSOx system. The circuit consists of N-series connected CCPS (capacitor charging power supply) and MPC Tank. The MPC power supply developed compared to the conventional LC resonant type has many advantage, it was verified reliability of a product by module, simulator and tank connection test. Now, the developed MPC power supply is installed POSCO sintering plant for DeSOx, DeNOx system.

• Journal of electromagnetic engineering and science
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• v.7 no.2
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• pp.64-68
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• 2007

An InGaP/GaAs HBT based differential Colpitts voltage control oscillator(VCO) is presented in this paper. In the VCO core, two switching transistors are introduced to steer the core bias current to save power. An LC tank with an inductor quality factor(Q) of 11.4 is used to generate oscillation frequency. It has a superior phase noise characteristics of -130.12 dBc/Hz and -105.3 at 1 MHz and 100 kHz frequency offsets respectively from the carrier frequency(1.566 GHz) when supplied with a control voltage of 0 volt. It dissipates output power of -5.3 dBm. Two pairs of on-chip base collector (BC) diodes are used in the tank circuit to increase the VCO tuning range(168 MHz). This VCO occupies the area of $1.070{\times}0.90mm^2$ including buffer and pads.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.1
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• pp.50-55
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• 2008

In this paper, New LC VCO with $8{\sim}10.9$ GHz Band has been designed using commercial $0.35-{\mu}m$ CMOS technology. This proposed circuit is consisted of the parallel construction of the typical NMOS and PMOS cross-coupled pair which is based on the LC tank, MOS cross-coupled pair which has same tail current of complementary NMOS and PMOS, and output buffer. The designed LC VCO, which is according to proposed structure in this paper, takes a 29% improvement of the wide tuning range as 8 GHz to 10.9 GHz, and a 6.48mW of low power dissipation. Its core size is $270{\mu}m{\times}340{\mu}m$ and its phase noise is as -117dBc Hz and -137dBc Hz at 1-MHz and 10-MHz offset, respectively. FOM of the new proposed LC VCO gets -189dBc/Hz at a 1-MHz offset from a 10GHz center frequency. This design is very useful for the 10Gb/s clock generator and data recovery integrated circuit(IC) and SONET communication applications.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.950-953
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• 1987

A wave difference method(WDH) phase detector for timing recovery is designed in the digital subscriber loop receiver. This paper describes the architecture and experimental results of the WDM, tankless timing extraction PLL. The results show that the designed WDM timing extraction circuit have stable jitter performance without the use of high precision LC tank circuit.