• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.206-211
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• 2005

The hearing aids specific operational amplifier described in this paper is a single-supply, low voltage CMOS amplifier. It works on 1.3V single-supply and gets a gain of 82dB. The 0.18${\mu}m$ CMOS process was chosen to reduce the driven voltage as well as the power dissipation.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.915-918
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• 2003

본 논문에서는 높은 슬루율을 가지고 전압편차 (offset)보상 기능을 가지면서도 전력소모가 적은 고계조 TFT-LCD 데이터 드라이버 구동용 단일이득 연산증폭기(unit gain op-amp)의 바이어스 회로 및 구동 방법을 제안하였다. 제안한 단일이득 연산증폭기는 일반적으로 사용되고 있는 전압편차 보상기능을 가진 단일이득 연산증폭기에 adaptive bias기능을 추가한 것으로써, 기존 구조에 비해 50%이상의 소비 전력 절감 효율을 보였다.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.908-919
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• 1998

This paper describes implementation and simulation of Chua's oscillator circuits with a cubic non-linear resistor. The two-terminal nonlinear resistor NR consists of one Op Amp two multipliers and five resistors. The Chua's oscillator circuit is implemented with analog electronic devices. Period-1 limit cycle period-2 limit cycle period-4 limit cycle and spiral attractor double-scroll attractor and 2-2 window are observed experimentally from the laboratory model and simulated by computer for the presented model. Comparing the result of experiments and simulations the spectrums are satisfied.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.637-638
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• 2006

A novel 1.2V class-AB output stage for the SW-OpAmp technique was presented. By using current mirrors and simple current extraction circuits, the proposed circuit boosts DM signal currents while eliminates CM ones to perform class-AB operation. Hspice simulation results verify the versatility of the proposed circuit technique.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1578-1581
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• 2009

This work describes a power and area efficient switched-capacitor cyclic DAC for mobile display drivers. The proposed DAC can be simply implemented with one opamp two capacitors and several switches. Furthermore, the op-amp input referred offset is attenuated at the DAC output without additional offset cancellation circuitry. The operation of the cyclic DAC is verified through circuit level simulations.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.120-121
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• 2014

장거리 이송이 가능한 선형동기 전동기 구조를 제안하고, 수학적 모델링을 하였으며, PI제어기를 포함하는 제어알고리즘을 제안하여, 실험으로 그 결과를 확인하였다. 추진제어기의 출력은 Park's, Clake's Transformation을 이용하여 코일을 구동하는 전류 명령을 발생시켰으며 개별 코일을 독립적으로 구동하는 아날로그 전류제어기를 OP-Amp로 구현하였다. 실험결과는 속도 오차는 4 ~ 10% 이하의 결과를 얻었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.5
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• pp.1310-1318
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• 1998

Sigma-delta converter is frequently used for conyerting low-frequency anglog to digital signal. The converter consists of a modulator and a digital filer, but our work is concentrated on the modulator. In this works, to design second-order sigma-dalta modulator with 14bit resolution, we define maximumerror limits of each components (operational smplifier, integrator, internal ADC, and DAC) of modulator. It is first performed modeling of an ideal second-order sigma-delta modulator. This is then modified by adding the non-ideal factors such as limit of op-amp output swing, the finit DC gain of op-amp slew rate, the integrator gian error by the capacitor mismatch, the ADC error by the cmparator offset and the mismatch of resistor string, and the non-linear of DAC. From this modeling, as it is determined the specification of each devices requeired in design and the fabrication error limits, we can see the final performance of modulator.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.1
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• pp.44-49
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• 2012

The indirect-contact ECG measurement is a newly developed method for unconstrained and nonconscious measurement in daily Life. This study is the first step to reducing the large background noise appearing in indirect-contact ECG. This study built the thermal noise model of capacitively coupled active electrode which is used in indirect-contact ECG. The results show that the level of thermal noise estimated by the thermal noise model is much the same as that of actual background noise for the capacitively coupled active electrode alone. By applying the actual electrical properties of a sample cotton cloth to the thermal noise model, the theoretical level of thermal noise in the indirect-contact ECG was estimated. The results also show that the level of op-amp's intrinsic noise is so small that it can be negligible in comparison with thermal noise of resistors. The relationship between the level of thermal noise and the resistance of the bias resistor was derived, and it is the base for the further study how to choice the optimal resistance for the bias resistor.

• Journal of electromagnetic engineering and science
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• v.14 no.2
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• pp.61-67
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• 2014

This paper presents a zero-IF CMOS RF receiver, which supports three channel bandwidths of 5/10/40MHz for LTE-Advanced systems. The receiver operates at IMT-band of 2,500 to 2,690MHz. The simulated noise figure of the overall receiver is 1.6 dB at 7MHz (7.5 dB at 7.5 kHz). The receiver is composed of two parts: an RF front-end and a baseband circuit. In the RF front-end, a RF input signal is amplified by a low noise amplifier and $G_m$ with configurable gain steps (41/35/29/23 dB) with optimized noise and linearity performances for a wide dynamic range. The proposed baseband circuit provides a -1 dB cutoff frequency of up to 40MHz using a proposed wideband OP-amp, which has a phase margin of $77^{\circ}$ and an unit-gain bandwidth of 2.04 GHz. The proposed zero-IF CMOS RF receiver has been implemented in $0.13-{\mu}m$ CMOS technology and consumes 116 (for high gain mode)/106 (for low gain mode) mA from a 1.2 V supply voltage. The measurement of a fabricated chip for a 10-MHz 3G LTE input signal with 16-QAM shows more than 8.3 dB of minimum signal-to-noise ratio, while receiving the input channel power from -88 to -12 dBm.

• Journal of IKEEE
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• v.17 no.1
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• pp.22-28
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• 2013

According to a survey, more than 50% of the elders fall which is the most frequent daily safety accident of the elders takes place at home. Furthermore, the elders fall is anticipated to increase as more elderly people are expected to live alone since, 67.1% of the elders of 65 or more do not hope to live with their children. This research aims to verify the fall by measuring and analyzing the floor vibration, and the hardware system was also designed was Piezo Film Sensor, Op-Amp, and DAQ. The system is consists of signal processing part for measuring floor vibration and alarm part for identifying the consciousness of the user when the fall occurs. The fall detection by vibration signals verified by k-Nearest Neighbor verification, and the results showed the error rate of 3.8%.