• 전기학회논문지
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• 제59권11호
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• pp.2089-2092
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• 2010

There are many cases that interrupt the production process because of malfunctions caused by electronic circuit boards which control equipment, but it is difficult to distinctly identify the causes in many cases. Especially, CMOS devices with the control logic circuit return automatically to normal state after their own faults. Therefore it is not easy to analyze the problems with electronic circuit boards. Recently, nuclear power plant experienced a failure due to the malfunction of electronic circuit boards and it was identified that the reason of the malfunction was because of latch-up phenomenon caused by external surge in electronic devices. This paper presents the causes and the phenomenon of latch-up by experiment and also a way using counter EMF diodes, noise filters and surge protective devices to prevent latch-up phenomenon from electronic circuit boards, finally confirms the effectiveness of the result by experiment.

• ETRI Journal
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• 제28권2호
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• pp.182-190
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• 2006

The circuit modeling of interdigitated capacitors fabricated by high-k low-temperature co-fired ceramic (LTCC) sheets was investigated. The s-parameters of each test structure were measured from 50 MHz to 10 GHz, and the modeling was performed using these measured sparameters up to the first resonant frequency. Each test structure was divided into appropriate building blocks. The equivalent circuit of each building block was composed based on the partial element equivalent circuit (PEEC) method. Modeling was executed to optimize the parameters in the equivalent circuit of each building block. The validity of the extracted parameters was verified by the predictive modeling for the test structures with different geometry. After that, Monte Carlo analysis and sensitivity analysis were performed based on the extracted parameters. The modeling methodology can allow a device designer to improve the yield and to save time and cost for the design and manufacturing of devices.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권9호
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• pp.531-538
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• 2005

This paper proposes an expert system which is able to enhance the accuracy and productivity by determining the test strategy based on heuristic rules for test of the hybrid electronic circuit board producted massively in production line. The test heuristic rules are obtained from test system designer, test experts and experimental results. The guarding method separating the tested device with circumference circuit of the device is adopted to enhance the accuracy of measurements in the test of analog devices. This guarding method can reduce the error occurring due to the voltage drop in both the signal input line and the measuring line by utilizing heuristic rules considering the device impedance and the parallel impedance. Also, PSA(Parallel Signature Analysis) technique Is applied for test of the digital devices and circuits. In the PSA technique, the real-time test of the high integrated device is possible by minimizing the test time forcing n bit output stream from the tested device to LFSR continuously. It is implemented in Visual C++ computer language for the purpose of the implementation of the inference engine using the dynamic memory allocation technique, the interface with the electronic circuit database and the hardware direct control. Finally, the effectiveness of the builded expert system is proved by simulating the several faults occurring in the mounting process the electronic devices to the surface of PCB for a typical hybrid electronic board and by identifying the results.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.535-538
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• 2005

We report the influence of the threshold voltage and mobility fluctuation in TFT on current mode digital circuit performance. We found that the threshold voltage showed more serious circuit malfunction. We studied new circuit configuration for improvement.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.66-69
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• 2004

This work is the study of Voltage-Down Converter used as internal supply voltage having large current driving and stable voltage level at any variation of process, voltage, and temperature(P.V.T). It converts VDD(external supply voltage) into $V_{1NT}(internal\;supply\;voltage).$ From the simulation results, a new Voltage-Down Converter has large current driving and a little stand-by current under lower supply voltage than conventional circuit. And bad characteristic of VINT, peaking, was eliminated. Start-up circuit for BGR is also added to one circuit, which consumes less current dissipation than convention circuit

• 조명전기설비학회논문지
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• 제28권1호
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• pp.1-8
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• 2014

The conventional Three-Stage electronic ballast is stable, but Two-Stage electronic ballast has been researching because of efficiency. Three-Stage electronic ballast is consisted of PFC circuit, buck converter, and inverter circuit, but Two-stage is consisted of PFC circuit, Buck-Inverter full bridge circuit. The Buck-Inverter full bridge inverter consists of two half bridge inverters for low frequency switching, and high frequency switching. In the case of street lamp it is far from a lamp to a ballast, the conventional pulsed high voltage ignitor can not turn on the HID lamps because of reduction of ignition voltage. Therefore, it needs to do the research on a resonant ignition to turn on the HID lamps. Therefore, in the Two-Stage electronic ballast which has the resonant tank for ignition, the transient resonant current because of low frequency changing is analyzed, the novel algorithm is proposed to resuce the transient current.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.778-781
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• 2002

In this paper, we designed the anti-fuse program circuit, and there are an anti-fuse program/sense/latch circuit, a negative voltage generator, power-up circuit and etc. in this circuit. An output voltage of a negative voltage generator is about -4,51V. We detected certainly it regardless of simulation result power rise time or temperature change to detect the anti-fuse program state of an anti-fuse program/sense/latch circuit and were able to know what performed a steady action. And as a result of having done a simulation while will change a resistance value voluntarily in order to check an anti-fuse resistance characteristic of this circuit oneself, it recognized as a programmed anti-fuse until 23k$\Omega$, and we were able to know that this circuit was a lot of margin than general anti-fuse resistance 500$\Omega$. Therefore, the anti-fuse program circuit of this study showed that was able to apply for configuration of the programmable logic device.

• 전력전자학회논문지
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• 제23권5호
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• pp.299-304
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• 2018

An ideal circuit breaker should supply electric power to loads without losses in a conduction state and completely isolate the load from the power source by providing insulation strength in a break state. Fault current is relatively easy to break in an Alternating Current (AC) circuit breaker because the AC current becomes zero at every half cycle. However, fault current in DC circuit breaker (DCCB) should be reduced by generating a high arc voltage at the breaker contact point. Large fire may occur if the DCCB does not take sufficient arc voltage and allows the continuous flow of the arc fault current with high temperature. A semiconductor circuit breaker with a power electronic device has many advantages. These advantages include quick breaking time, lack of arc generation, and lower noise than mechanical circuit breakers. However, a large load capacity cannot be applied because of large conduction loss. An extinguishing technology of DCCB with polymeric positive temperature coefficient (PPTC) device is proposed and evaluated through experiments in this study to take advantage of low conduction loss of mechanical circuit breaker and arcless breaking characteristic of semiconductor devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2088-2090
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• 1998

A low-cost electronic starter is developed to decrease ignition failure significantly through successive starting trial and to prevent overheating at the end of fluorescent lamp life. Moreover, it has an additional feature of being capable of ignition at the recovered lamp voltage without any circuit correction. The developed electronic starter is consisted of four parts - a half wave rectifier circuit, a timer circuit, a switching circuit and a protection circuit. The protection circuit made up of a transistor and capacitors utilizing capacitive characteristics, carries out successive starting trial and end-of-life protection. Lamp ignition is completed within 0.5 seconds with taking advantage of a high preheating current from the half-wave rectifier circuit. Nevertheless, its performance is proved to be very excellent through a standard switching endurance test.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2196-2198
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• 2001

Because the circuit board has the structure connected by circuit patterns, the work to test whether the analog devices or circuits such as resisters, capacitors, inductors, diodes, etc. on the tested board is goof or not is very difficult. This paper proposes the test method of identifing the faulted devices or faulted circuit on the circuit board using guarding circuit. The guarding method is the techniqus measuring accurately the value of the devices by separating the electronic devices to be tested from around it. Finally, the availability and accuracy of the proposed test method is verified by applying the technique to a test electronic circuit.