• ETRI Journal
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• v.29 no.1
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• pp.70-78
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• 2007

A new low-voltage CMOS interface circuit with digital output for piezo-resistive transducer is proposed. An input current sensing configuration is used to detect change in piezo-resistance due to applied pressure and to allow low-voltage circuit operation. A simple 1-bit first-order delta-sigma modulator is used to produce an output digital bitstream. The proposed interface circuit is realized in a 0.35 ${\mu}m$ CMOS technology and draws less than 200 ${\mu}A$ from a single 1.5 V power supply voltage. Simulation results show that the circuit can achieve an equivalent output resolution of 9.67 bits with less than 0.23% non-linearity error.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.981-987
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• 1986

This paper describes the CIREX(CIRcuit EXtractor), an automated CMOS circuit extraction program which provides SPICE2 input file by computing circuit connectivity and transistor dimensions from the CIF file. The CIREX also computes parasitic capacitance and resistance which makes it a valuable tool for timing analysis and detailed circuit simulation. A lattice model is used to calculate the interconnection resistances and substrate capacitances which can be replaced, as an option, by a node model for the worst case timing analysis of the circuit.

• Journal of The Korean Association For Science Education
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• v.19 no.4
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• pp.570-584
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• 1999

The units about electricity in 5th and 6th science curriculum for elementary school was analyzed and the elementary students' understanding of related concepts was investigated. This study was to make connection between the research about alternative concepts and writing textbooks. It was found that students' response had following characteristics. They had strong belief that the + and - ends of battery should be connected. However this belief was not complete because students did not understand that the other circuit elements had to be connected properly. When the circuit involve more than one bulbs or batteries, they counted the number of batteries or bulbs only and paid little attention to the connection of them. In explaining circuits and the brightness of the bulbs in the circuits. students tried to explains the circuit using scientific terms but failed to used them properly. Although the concept of resistance was not dealt explicitly. student had reasonable qualitative understanding about resistance. According to response of students, several suggestions might be made for the curriculum. The structure and the circuit elements and the proper connection needs to be taught. Also more emphasis is necessary to pay attention to the connection in addition to the numbers of bulbs or batteries. Finally, it needs to be investigated carefully if it is better to introduce some qualitative model to explain the amount of current through bulb depending on the connection and the number of bulbs. It might also be better to introduce some terms, such as current and resistance with the model.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.9
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• pp.831-838
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• 2014

Chip on glass (COG) bonding using anisotropic conductive film (ACF) is a key technology to assemble a driver IC onto a LCD glass panel. In this paper, an experimental investigation was conducted to investigate the correlation between contact resistance and characteristics of image taken by machine vision based inspection system. The results show that the contact resistance was strongly influenced by the contrast ratio of conductive particle rather than the number of conductive particles. Also, number of conductive particles whose contrast ratio is below 0.75 is crucial for determining the quality of the assembled samples. On the other hand, in the result of high temperature high humidity storage test, the contrast ratio of samples was increased. However, in the case of open-circuit samples after temperature humidity storage test, the number of conductive particles whose contrast ratio is above 0.75 was more than that of the closed-circuit samples.

• Journal of Welding and Joining
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• v.13 no.3
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• pp.55-64
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• 1995

Metallizing method on ceramic surface is one of the compositing technology of ceramics and metal. The purpose of this study is to make HIC (Hybrid Intergrated Circuit) with copper metallizing method of which copper layer is formed on ceramic substrate by firing in atmosphere in lieu of conventional hybrid microcircuit systems based on noble metal. Metallizing pastes were made from various copper compounds such as Cu$_{2}$O, CuO, Cu, CuS and kaolin. And the screen printing method was used. The characteristics of metallized copper layers were analyzed through the measurement of sheet resistance, SEM, and EDZX. The results obtainted are summarized as follows; 1. The copper metallizing layers on ceramic surface can be formed by firing in air. 2. The metallized layer using Cu$_{2}$O paste showed the smallest sheet resistance among a group of copper chemical compounds. And optimum metallizing conditions are 15 minutes of firing time, 1000.deg.C of firig temperature, and 3 minutes of deoxidation time. 3. The results of EDAX analysis showed mutual diffusion of Cu and Al. 4. The kaolin plays a important role of deepening the penetration of Cu to $Al_{2}$O$_{3}$ ceramics. But if the kaolin content is too much, sheet resistance increases and copper metallizing layer becomes brittle.

• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.5
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• pp.1-5
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• 1975

접합형 트린지스터와 발광다이오드(LED) 및 광도전소자(CdS)로서 구성된 광결합 전류안정부저항회로를 진안하였다. 이는 일반적으로 광트랜지스터보다도 더 예민한 것을 이용하여, CdS와 LED를 밀착 시켜서 LED에 흐르는 전류와 CdS의 실효저항변화로써 결합된 광결합방식을 택하였다. 트랜지스터의 콜랙터-에미터간에 인위적인 누변저항을 삽입하는 방법을 도입함으로써 부저항치 및 최대입력단자전압치를 임의로 변화할 수 있게 하였으며, 제안한 회로를 분석하고 또 이를 실험적으로 확인하였다. 누변저항을 1KΩ에서 30KΩ까지 변화시켰을 때 최대입력단자전압은 1.65V에서 4.22V로 변하였고, 부저항치는 -1.0KΩ에서 -10.0KΩ까지 변하였다. 또 실험치에 대한 계산치에의 상대백분최대오차가 11%이었다. A current stable negative resistance circuit has been constucted with combination of coulplementary symmetrical transistors, a light emitting diode and a photoconductive cell. The negative resistance(Rn) and break-over voltage(VBo) can be set at a designed value according to adjustment of the artificial leakage resistance of p-n-p transistor. The RN and VBo calculated in this designed circuit are checked though the experiments, the errors are found less than 11%.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.13-20
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• 2020

Accurate parameters based on equivalent circuit are required for high-performance field-oriented control in a three-phase induction motor. In a normal case, stator resistance can be accurately measured using a measuring equipment. Except for stator resistance, all machine parameters on the equivalent circuit should be estimated with particular algorithms. In the viewpoint of traditional regions, the parameters of an induction motor can be identified through the no-load and standstill test. This study proposes an identification method that uses the d-axis model of the induction motor in a stationary frame with the predefined information on stator resistance. Mutual inductance is estimated on the rotational dq coordination similar to that in the traditional no-load experiment test. The leakage inductance and rotor resistance can be estimated simply by applying different voltages and frequencies in the d-axis model of the induction motor. The proposed method is verified through simulation and experimental results.

• Journal of IKEEE
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• v.18 no.4
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• pp.586-592
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• 2014

In this paper, high efficiency power management IC(PMIC) with DT-CMOS(Dynamic threshold voltage Complementary MOSFET) switching device is presented. PMIC is controlled PWM control method in order to have high power efficiency at high current level. The DT-CMOS switch with low on-resistance is designed to decrease conduction loss. The control parts in Buck converter, that is, PWM control circuit consist of a saw-tooth generator, a band-gap reference(BGR) circuit, an error amplifier, comparator circuit, compensation circuit, and control block. The saw-tooth generator is made to have 1.2MHz oscillation frequency and full range of output swing from supply voltage(3.3V) to ground. The comparator is designed with two stage OP amplifier. And the error amplifier has 70dB DC gain and $64^{\circ}$ phase margin. DC-DC converter, based on current mode PWM control circuits and low on-resistance switching device, achieved the high efficiency nearly 96% at 100mA output current. And Buck converter is designed along LDO in standby mode which fewer than 1mA for high efficiency. Also, this paper proposes two protection circuit in order to ensure the reliability.

• Journal of Sensor Science and Technology
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• v.15 no.1
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• pp.34-39
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• 2006

This study provides the electrical model of combustible catalytic gas sensor. Physical characteristics such as thermal behavior, resistance change were included in this model. The finite element method analysis for sensor device structure showed that the thermal behavior of sensor is expressed in a simple electrical equivalent circuit that consists of a resistor, a capacitor and a current source. This thermal equivalent circuit interfaces with real electrical circuit using two parts. One is 'power to heat' converter. The other is temperature dependent variable resistor. These parts realized with the analog behavior devices of the SPICE library. The gas response tendency was represented from the mass transferring limitation theory and the combustion theory. In this model, Gas concentration that is expressed in voltage at the model, is converted to heat and is flowed to the thermal equivalent circuit. This model is tested in several circuit simulations. The resistance change of device, the delay time due to thermal capacity, the gas responses output voltage that are calculated from SPICE simulations correspond well to real results from measuring in electrical circuits. Also good simulation result can be produced in the more complicated circuit that includes amplifier, bios circiut, buffer part.

• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.155-161
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• 2007

A new and simple method of 3-dimensional circuit modeling and analysis is proposed and verified experimentally for the first time by determining 3-dimensional current flow and 2-dimensional light distribution in blue InGaN/GaN multi-quantum well (MQW) light emitting diode (LED) devices. Circuit parameters of the LED consist of the resistance of the metallic film and epitaxial layer, and the intrinsic diode which represents the active region emitting the light. The circuit parameters are extracted from the transmission line model (TLM) and current-voltage relation. We applied the >> proposed method and extracted circuit parameters to obtain the light emission pattern in a top-surface emitting-type LED. The current spreading effect is analyzed theoretically and quantitatively with a variation of the resistance of metallic and epitaxial layers. The emitting-light distribution of the fabricated blue LED showed a good agreement with the analyzed result, which shows the dark emission intensity at the corner of the p-electrode.