• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.398-402
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• 2003

본 논문에서는 FMCW레이더 시스템에서 안정된 소스원으로 사용할 수 있는 전압제어 유전체 공진 발진기를 구현하였다. 위상 잡음을 개선하기 위하여 저잡음 특성을 가진 MESFET과 높은 선택도의 유전체 공진기를 사용하였고, 안정된 전압 가변을 하기 위하여 Q값이 높고 가변 특성이 좋은 바렉터 다이오드를 사용하였다. 구현된 회로는 최적의 성능을 갖도록 하모닉 발란시스 시뮬레이션을 사용하였다. 제작된 전압제어 유전체 공진 발진기의 특성을 측정한 결과, 중심 주파수 12.0GHz에서 2.22dBm 출력 파워와 -30dBc의 고조파 억압과 중심 주파수 100kHz offest에서 -130dBc의 매우 좋은 위상잡음 특성을 얻었으며, 바렉터 다이오드에 인가되는 전압의 변화에 따른 주파수 가변 범위는 중심주파수에서 $\pm$18.7MHz를 얻었다. 제작된 VCDRO는 FMCW의 국부 발진기로 이용될 수 있음을 확인하였다.

• 전자공학회논문지T
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• 제35T권1호
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• pp.48-58
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• 1998

본 논문은 센서에서 수반되는 기생용량과 온도 드리프트 및 누설전류의 영향을 경감하기 위한 C-V변환회로 및 C-V변환회로에 관한 실험결과를 제시하고, 또한 논문에서 제안한 센싱 주파수를 기준주파수로 나누어줌으로써 상기 영향들을 줄일 수 있는 새로운 인터페이스 회로를 제시한다 이 회로는 용량비의 출력신호를 디지털 방식으로 16진수로 계수 함으로써 신호의 전송이나 컴퓨터 처리가 쉬울 뿐 아니라 비트수의 증가에 따라 분해 능을 향상시킬 수 있는 이점도 있다. 시작한 인터페이스 회로의 C-V 및 C-F 변환회로에서 전원전압 4.0V, 피이드백 커패시턴스10pF, 압력 0∼10 KPa범위에서 감도는 각각 28 ㎷/㎪·V, -6.6 ㎐/㎩로서 양호하였고, 온도 드리프트 특성은 0.051 %F.S./℃ 및 0.078 %F.S./℃로서 크게 개선되었다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권2호
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• pp.98-107
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• 2013

This work describes a 13b 100 MS/s 0.13 um CMOS four-stage pipeline ADC for 3G communication systems. The proposed SHA-free ADC employs a range-scaling technique based on switched-capacitor circuits to properly handle a wide input range of $2V_{P-P}$ using a single on-chip reference of $1V_{P-P}$. The proposed range scaling makes the reference buffers keep a sufficient voltage headroom and doubles the offset tolerance of a latched comparator in the flash ADC1 with a doubled input range. A two-step reference selection technique in the back-end 5b flash ADC reduces both power dissipation and chip area by 50%. The prototype ADC in a 0.13 um CMOS demonstrates the measured differential and integral nonlinearities within 0.57 LSB and 0.99 LSB, respectively. The ADC shows a maximum signal-to-noise-and-distortion ratio of 64.6 dB and a maximum spurious-free dynamic range of 74.0 dB at 100 MS/s, respectively. The ADC with an active die area of 1.2 $mm^2$ consumes 145.6 mW including high-speed reference buffers and 91 mW excluding buffers at 100 MS/s and a 1.3 V supply voltage.

• 전기학회논문지
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• 제66권2호
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• pp.328-338
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• 2017

In this paper, a zero torque control scheme adopting current sharing function (CSF) used in integrated Switched Reluctance Motor (SRM) drive with DC battery charger is proposed. The proposed control scheme is able to achieve the keeping position (KP), zero torque (ZT) and power factor correction (PFC) at the same time with a simple novel current sharing function algorithm. The proposed CSF makes the proper reference for each phase windings of SRM to satisfy the total charging current of the battery with zero torque output to hold still position with power factor correction, and the copper loss minimization during of battery charging is also achieved during this process. Based on these, CSFs can be used without any recalculation of the optimal current at every sampling time. In this proposed integrated battery charger system, the cost effective, volume and weight reduction and power enlargement is realized by function multiplexing of the motor winding and asymmetric SR converter. By using the phase winding as large inductors for charging process, and taking the asymmetric SR converter as an interleaved converter with boost mode operation, the EV can be charged effectively and successfully with minimum integral system. In this integral system, there is a position sliding mode controller used to overcome any uncertainty such as mutual inductance or DC offset current sensor. Power factor correction and voltage adaption are obtained with three-phase buck type converter (or current source rectifier) that is cascaded with conventional SRM, one for wide input and output voltage range. The practicability is validated by the simulation and experimental results by using a laboratory 3-hp SRM setup based on TI TMS320F28335 platform.

• 한국산업정보학회논문지
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• 제18권5호
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• pp.9-14
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• 2013

본 논문은 DLL 기술을 사용하여서 낮은 위상잡음을 갖는 주파수 체배기를 설계 하였다. VCDL은 공통모드 잡음을 줄이기 위해서 차동구조를 이용하여 설계 되었다. 이번 설계는 65nm, 1.2V TSMC CMOS 공정을 이용 하였고, 동작 주파수 범위는 10MHz에서 24MHz로 측정되었다. TCXO를 기준 주파수로 사용하여 위상잡음을 측정하였을 때 38.4MHz의 출력에서 1MHz offset 기준으로 -125dBc/Hz가 측정되었다. 총 면적은 $0.032mm^2$을 사용하였고, 출력 버퍼를 포함하여 총 1.8mA의 전류를 칩에서 소비하였다.

• ETRI Journal
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• 제38권4호
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• pp.685-694
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• 2016

A surface micromachined piezoresistive pressure sensor with a novel internal substrate vacuum cavity was developed. The proposed internal substrate vacuum cavity is formed by selectively etching the silicon substrate under the sensing diaphragm. For the proposed cavity, a new fabrication process including a cavity side-wall formation, dry isotropic cavity etching, and cavity vacuum sealing was developed that is fully CMOS-compatible, low in cost, and reliable. The sensitivity of the fabricated pressure sensors is 2.80 mV/V/bar and 3.46 mV/V/bar for a rectangular and circular diaphragm, respectively, and the linearity is 0.39% and 0.16% for these two diaphragms. The temperature coefficient of the resistances of the polysilicon piezoresistor is 0.003% to 0.005% per degree of Celsius according to the sensor design. The temperature coefficient of the offset voltage at 1 atm is 0.0019 mV and 0.0051 mV per degree of Celsius for a rectangular and circular diaphragm, respectively. The measurement results demonstrate the feasibility of the proposed pressure sensor as a highly sensitive circuit-integrated pressure sensor.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.213-216
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• 2004

This paper describes design and implementation of the 5.5 GHz VCO with parallel-branch inductors using 0.8${\mu}m$ SiGe HBT process technology. The proposed parallel-branch inductor shows $12 \%$ improvement in quality factor in comparison with the conventional inductor. A phase noise of -93 dBc/Hz is measured at 100 kHz offset frequency, and the harmonics in the VCO are suppressed less than -23 dBc. The single-sided output power of the VCO is -6.5$\pm$1.5 dBm. The manufactured VCO consumes 15.0 mA with 2.5 V supply voltage. Its chip areas are 1.8mm ${\times}$ 1.2mm.

• 전기학회논문지P
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• 제55권1호
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• pp.26-30
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• 2006

For the purpose of developing capacitive humidity sensor having interdigital electrodes, interdigital electrode was modeled and simulated to obtain capacitance and sensitivity as a function of geometric parameters like the structural gap and thickness. For the development of ASIC, switched capacitor signal processing circuits for capacitive humidity sensor were designed and simulated by Cadence using $0.25{\mu}m$ CMOS process parameters. The signal processing circuits are composed of amplifier for voltage gain control, and clock generator for sensor driving and switch control. The characteristics of the fabricated sensors are; 1) sensitivity is 9fF/%R.H., 2) temperature coefficient of offset(TCO) is $0.4%R.H./^{\circ}C$, 3) nonlinearity is 1.2%FS, 4) hysteresis is 1.5%FS in humidity range of $3%R.H.{\sim}98%R.H.$. The response time is 50 seconds in adsorption and 70 seconds in desorption. Fabricated process used in this capacitive humidity sensor having interdigital electrode are just as similar as conventional IC process technology. Therefore this can be easily mass produced with low cost, simple circuit and utilized in many applications for both industrial and environmental measurement and control system, such as monitoring system of environment, automobile, displayer, IC process room, and laboratory etc.

• 한국전자파학회논문지
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• 제15권11호
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• pp.1075-1081
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• 2004

본 논문에서는 PHEMT의 소 신호 산란계수를 이용하여 일본에서 사용하는 X-band 대역의 차량 속도 사전 제한 경보기용(Radar Detector) 전압제어 발진기를 설계 제작하였다. 전압 제어 발진기를 구현하기 위해서 넓은 동조 범위와 직렬저항이 0옴인 바렉터 다이오드를 사용하였고, 트랜지스터의 작동전압과 공진 주파수를 결정하는 마이크로 스트립 선로와 바렉터 소자와의 반사계수를 조정하여 위상잡음은 10kHz 오프셋에서 -85 dBc/Hz, 기본 주파수 신호 출력 크기는 +4.5 dBm, 제2고조파 억제는 -25.6 dEc를 얻었다. 본 논문에서 제작한 샘플이 감도에서 기존 제품들보다 우수한 특성이 나오는 것을 확인할 수 있었다.

• 전기학회논문지
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• 제56권1호
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• pp.214-221
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• 2007

This paper presents a myoelectric hand prosthesis(MHP) with two degree of freedom(2-DOF), which consists of a mechanical hand, a surface myoelectric sensor(SMES) for measuring myoelectric signal, a control system and a charging battery. The actuation for the 2-DOF hand functions such as grasping and wrist rotation was performed by two DC-motors, and controlled by myoelectric signal measured from the residual forearm muscle. The grip force of the MHP was automatically changed by a mechanical automatic speed reducer mounted on the hand. The skin interface of SMES was composed of the electrodes using the SUS440 metal in order to endure a wet condition due to the sweat. The sensor was embedded with a amplifier and a filter circuit for rejecting the offset voltage caused by power line noises. The control system was composed of the grip force sensor, the slip sensor, and the two controllers. The two controllers were made of a RISC-type microprocessor, and its software was executed on a real-time kernel. The control system used Force Sensing Resistors, FSR, as slip pick-ups at the fingertip of a thumb and the grip force information was obtained from a strain-gauge on the lever of the MHP. The experimental results were showed that the proposed control system is feasible for the MHP.