• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.322-325
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• 2002

In this study, noise figures of 0.3 $\mu\textrm{m}$-GaAs MESFETs are predicted experimentally with different temperatures. Both the noise figure and the gate leakage current are obtained with wide range of temperatures(27$^{\circ}C$∼300$^{\circ}C$). From the results, gate leakage current increases with temperatures. It is expected that gate leakage current contributes directly to the increase of shot noise current. It is therefore highly recommended to apply an accurate noise analysis to the design of the devices and modules at high temperatures. Fini,Uy the relation between the gate currents resulting in the increase of noise and the noise figures of submicron GaAs MESFETs are traced with different temperatures

• Journal of Power Electronics
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• 제19권1호
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• pp.278-287
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• 2019

In this study, a zero-crossing spike current issue in a totem-pole bridgeless power factor correction (PFC) converter is comprehensively investigated for the first time. Spike current occurs when input voltage crosses zero, becomes a noise source, and causes severe common mode emission issues. A generation mechanism for electromagnetic interference (EMI) is presented to investigate the EMI problem caused by zero-crossing issue, and a noise spectrum due to this issue is predicted by a theoretical analysis based on the Fourier coefficient of an approximate spike current waveform. Furthermore, a noise reduction method is proposed and then improved to reduce the spike current. Experimental measurements are implemented on a GaN-based totem-pole bridgeless PFC converter, and the spike current can be effectively suppressed through the proposed method. Furthermore, the noise spectrums measured without and with the reduced zero-crossing spike current are compared. Experimental results validate the analysis of the noise spectrum caused by the zero-crossing spike current issue.

• 대한전자공학회논문지
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• 제9권5호
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• pp.34-42
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• 1972

전류잡음은 탄소피막고정저항기의 품질을 나타내는 중요한 척도이다. 저항체피막상의 결함은 전류밀도의 불균형을 초래하고 결과적으로 전류잡음의 기대를 유발한다. 전류잡음의 크기는 저항재의 고유한 성질과 저항체의 처리, 조립 및 외장 등에 의한 여러 요인에 의존하고 있으나 각종 수명시험결과 저항기의 전기적특성과 전류잡음문에는 명백한 관계가 성립하고 있다. 대표군의 저항기에 대한 전류잡음지수의 정규분포를 표시하는 parameter를 해석하면 제품의 품질관리와 생산의 균일성을 판단하는 지표로서 매우 유용한 수단이다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권1호
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• pp.29-36
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• 2009

Power supply noise is fundamentally caused by large current peaks. Since large current peaks are induced by simultaneous switching of many circuit elements, power supply noise can be minimized by deliberate clock scheduling which utilizes nonzero clock skew. In this paper, nonzero skew clock scheduling is used to avoid the large peak current and consequently reduce power supply noise. While previous approaches require extra characterization efforts to acquire current waveform of a circuit, we approximate it only with existing cell library information to be easily adapted to conventional design flow. A simulated annealing based algorithm is performed, and the peak current values are estimated for feasible clock schedules found by the algorithm. The clock schedule with the minimum peak current is selected for a solution. Experimental results on ISCAS89 benchmark circuits show that the proposed method can effectively reduce the peak current.

• 한국소음진동공학회논문집
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• 제18권7호
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• pp.783-789
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• 2008

This experimental study describes the noise reduction and the feasibility of short current of a silencer for a high voltage COS(cut out switch) fuse of a transformer. When a high voltage COS fuse becomes a short circuit by the over current, the strong impulse noise over 150 dB(A) is generated. For the purpose of the reduction of impulse noise, in this study, the diffuser type and the reactive type silencers have been designed and tested, respectively. And also the electrical test on the short current is performed. From the experimental results, the well designed reactive type silencer has been shown to have the noise reduction of about 20 dB(A). It has been found that the feasibility of short current for the COS fuse is closely related to the porosity of the silencer.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1142-1147
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• 2002

For the evaluation of the DC motor noise and vibration, usually it is rely on human feeling because some kinds of noise are not definitely represented by measurement Instrument such as sound meter. But when we consider time signal of the noise and vibration. It is possible to represent them. And in this paper. it is suggested to study output current shape of the motor because it Is the source to make speed and torque variation of the motor. If the current shape is not stable. it makes operating state of the motor unstable and produces noise and vibration. By analyzing signal at time and frequency of noise and vibration and current shape. it is possible to automation of the noise and vibration measurement in the Production line.

• 전기학회논문지
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• 제66권1호
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• pp.194-202
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• 2017

In this study, we measured and analyzed electrical noise signals present in devices and systems operated in industrial facilities. Based on the analytic findings, we studied the most effective improvement measures for eliminating such noise signals. Leakage current and ground current generate data interferences in communication systems, and therefore we measured leakage current and ground current. We also measured and analyzed electrical noises in power systems to predict noise pathways and interference routes. Furthermore, we proposed the most effective and reliable improvement measures for blocking off various noise signals and safely eliminating them by improving the internal wiring of the facilities and grounding systems. As a final step, we conducted the proposed improvement measures and confirmed that they helped to improve the operations of the device sand systems in service by re-measuring electrical noise signals and comparing them with those measured before the proposed improvement measures were implemented.

• 한국소음진동공학회논문집
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• 제21권12호
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• pp.1177-1184
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• 2011

One of the main objectives of noise control act is to define and ensure application and respect of noise exposure limits. Most advanced countries have prepared a legal framework for noise limits either by national laws, ordinances or municipal by-laws. A large number of advaced countries have adopted the Leq index for the main sources of noise(road, railway, industry). The exception is aircraft noise for which regulatory practice is highly disparate. These differences in the indices adopted, the periods and areas to which regulations apply, definitions of measurement conditions and ways in which noise levels are calculated make it difficult to compare the current advanced countries standards. This study presents the current noise abatement policy of the advanced countries and proposes the improvement of the current noise abatement policy of Korea to catch up with it of the advanced countries.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.558-567
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• 2011

One of the main objectives of noise control act is to define and ensure application and respect of noise exposure limits. Most advanced countries have prepared a legal framework for noise limits either by national laws, ordinances or municipal by-laws. A large number of advaced countries have adopted the $L_{eq}$ index for the main sources of noise (road, railway, industry). The exception is aircraft noise for which regulatory practice is highly disparate. These differences in the indices adopted, the periods and areas to which regulations apply, definitions of measurement conditions and ways in which noise levels are calculated make it difficult to compare the current advanced countries standards. This study presents the current noise abatement policy of the advanced countries and proposes the improvement of the current noise abatement policy of Korea to catch up with it of the advanced countries.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권7호
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• pp.374-379
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• 2006

The switch mode power supply is a source of EMI with other equipment as well as with its own proper operation because of rapid changes in voltages and currents within a switching converter. The EMI is transmitted in two forms: radiated and conducted. Conducted noise consists of two categories known as the differential mode and the common mode. Common mode noise current is a major source of EMI in the switch mode Power supply. Recently, a current balancing technique has been studied to reduce the common mode noise. This paper investigates the reduction of common mode noise according to a node expansion of the switch mode power supply which is based on a current balancing technique. In this paper, seven PCB patterns of the forward converter are manufactured and experimented.