• 한국전자통신학회논문지
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• 제9권3호
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• pp.279-284
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• 2014

본 논문에서는 p-채널 저온 다결정 실리콘 박막 트랜지스터의 문턱전압 변동을 보상할 수 있는 새로운 OLED 화소회로를 제안하였다. 제안한 5-TFT OLED 화소회로는 4개의 스위칭 박막 트랜지스터, 1개의 OLED 구동 박막 트랜지스터 및 1개의 정전용량으로 구성되어 있다. 제안한 화소회로의 한 프레임은 초기화 구간, 문턱전압 감지 및 데이터 기입 구간, 데이터 유지 구간 및 발광 구간으로 나누어진다. SmartSpice 시뮬레이션 결과, 구동 트랜지스터의 문턱전압이 ${\pm}0.25V$ 변동 시 최대 OLED 전류의 오차율은 -4.06%이였고 구동 트랜지스터의 문턱전압이 ${\pm}0.50V$ 변동 시 최대 OLED 전류의 오차율은 9.74%였다. 따라서 제안한 5T1C 화소회로는 p-채널 다결정 실리콘 박막 트랜지스터의 문턱전압 변동에 둔감하여 균일한 OLED 전류를 공급함을 확인하였다.

• 한국전자통신학회논문지
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• 제8권2호
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• pp.207-212
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• 2013

본 논문에서는 n-채널 저온 다결정 실리콘 박막 트랜지스터의 문턱전압 변동을 보상할 수 있는 전압 기입 AMOLED 화소회로를 제안하였다. 제안한 6T1C 화소회로는 5개의 스위칭 박막 트랜지스터, 1개의 OLED 구동 박막 트랜지스터 및 1개의 정전용량으로 구성되어 있다. SmartSpice 시뮬레이션 결과, 구동 트랜지스터의 문턱전압이 ${\pm}0.33$ V 변동시 최대 OLED 전류의 오차율은 7.05 %이고 Vdata = 5.75 V에서 OLED 양극 전압 오차율은 0.07 %로 제안한 6T1C 화소회로가 구동 트랜지스터의 문턱전압 변동에도 균일한 OLED 전류를 공급함을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1555-1558
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• 2008

Various approaches were undertaken by major PDP makers in order to improve the luminous efficacy of the plasma discharge cells. There have been many reports that state that using a high Xe content PDP is one of the most promising key technologies available to improve the luminous efficacy. In the case of the higher Xe content panel, the higher address and sustain voltage were needed to drive the panel under the same reset condition. In this study, a variety of Xe content panels were investigated in order to examine wall voltage transfer behaviors. The transferred wall voltage status after addressing discharge at the same driving condition was analyzed by comparing Vt close curve of high and low Xe content panels. Through this analysis of Vt close curve difference, the driving waveform of a high Xe panel was quantitatively adjusted Under the same address voltage condition, results showed that the amount of the transferred wall voltage and Vt close curve after addressing discharge was matched for the first sustain discharge. Taking these results into consideration, we conclude that the driving waveform for different Xe content panels could be designed for the desired addressing discharge condition and the wall voltage state of the cell could be quantitatively controlled and measured through these approaches.

• 전자공학회논문지SC
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• 제38권2호
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• pp.38-49
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• 2001

본 논문은 IC chip내에서 전압을 낮추는 목적으로 사용되는 VDC 회로의 주파수 특성을 향상시키기 위한 새로운 회로를 제안한다. 제안된 회로에는 적응 바이어싱 방법을 통해 저전력소모 및 고속동작을 동시에 만족하는 두 개의 센서와 이 센서로 구동되는 3개의 transistor가 부가적으로 첨가되어 구동 transistor의 gate 충.방진 전류를 보상하여 구동회로의 정상동작을 유지시켜준다. 본 연구에 사용된 회로는 $0.62{\mu}m$ N well CMOS 공정을 사용하였으며, H spice simulation 결과, 내부전압의 변화폭은 부하전류가 0에서 $200m{\Lambda}$까지 5ns동안 증가할 경우 약 1.0V로, $200m{\Lambda}$에서 0으로 감소할 경우 약 0.6V로, 내부전압 회복시간은 증가시 7ns, 감소시 10ns로, 일반적인 구동방식에 비해 성능이 향상되었으며 전체 회로에 소모하는 power는 약 1.2mW로 매우 작았다.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.53-57
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• 2012

In this paper, by designing 20 W class driving circuit for driving high-power LED (Light Emitting Diode), we are going to comparatively carry out the analysis of characteristics for power circuit according to each design method. In this case, 200 V 60 Hz was performed as input data. The electrical characteristics such as voltage, current and ripple are checked for constant current circuit and constant voltage circuit in the LED module. In addition, as the ripple has an influence on illumination of LED light, low temperature working (-20 [$^{\circ}C$]) and high temperature working(80 [$^{\circ}C$]) are measured to make sure the ripple characteristics in accordance with temperature. In low temperature operation -20 [$^{\circ}C$] measurements, both constant current circuit and constant-voltage circuit were less impacted on input fluctuation, whereas in the high temperature operation 80 [$^{\circ}C$], current voltage in constant voltage circuit was surge after 430 [hour]. Voltage current ripple of constant current circuit was much less than constant voltage circuit, therefore we can show that constant current circuit is more stable.

• 한국전기전자재료학회논문지
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• 제17권2호
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• pp.171-177
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• 2004

Voltage step-down characteristics in Ring/Dot type piezoelectric transformer were examined as a function of the area of input electrode when the area of output electrode is fixed. The effects of driving frequency and load resistance on the voltage step-down characteristics were also examined. Voltage gain was greatly dependent on the driving frequency and load resistance, and showed a maximum gain at resonance frequency of the step-down transformer. The frequency where the maximum cutout voltage appears increased about 0.2％ as the load resistance increased from 10 to 150 Ω. As the area of input electrode increased, the voltage gain and the efficiency of the transformer increased. Frequency dependence of efficiency of the step-down transformer revealed a similar tendency with the voltage gain curves. The maximum efficiency remarked 94% when the input voltage and the load resistance were 20 Vpp and 120 Ω, respectively.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권2호
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• pp.190-196
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• 2013

It presents a unification of buck-boost and flyback converter for driving a cascaded H-bridge multilevel inverter with a single independent DC voltage source. Cascaded H-bridge multilevel inverter is useful to make many output voltage levels for sinusoidal waveform by combining two or more H-bridge modules. However, each H-bridge module needs an independent DC voltage source to generate multi levels in an output voltage. This topological characteristic brings a demerit of increasing the number of independent DC voltage sources when it needs to increase the number of output voltage levels. To solve this problem, we propose a converter combining a buck-boost converter with a flyback converter. The proposed converter provides independent DC voltage sources at back-end two H-bridge modules. After analyzing theoretical operation of the circuit topology, the validity of the proposed approach is verified by computer-aided simulations using PSIM and experiments.

• 한국전기전자재료학회논문지
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• 제33권6호
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• pp.475-482
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• 2020

For electronic paper displays using electrophoresis, the response time and reflectivity of the image panel fabricated by filtering are analyzed. For the filtering process, a square wave and ramp wave are applied to white charged particles with a unique q/m value. We divide the sample panels into #1 to #4 according to the applied waveform in the filtering process. Step waves comprising two steps are used to drive the panel; therefore, we divide the driving conditions into D1~D4. The applied voltage at the first stage of the half cycle of the driving waveform moves the charged particles attached via the image force from the electrode, and the applied voltage at the second stage moves the floating charged particles by detaching. As mentioned, four types of driving conditions (D1 to D4) classified according to the half cycle of the driving waveform are applied to the samples #1 to #4), which are classified according to four types of filtering process. When driving condition D1 is applied to the four types of sample panels, the rise time of #1 is 1.59s, #2 is 1.706s, #3 is 1.853s, and #4 is 1.235s, resulting in #4 being relatively faster compared with other sample panels, and showing the same trend in other driving conditions. As a result, we confirm that applying the driving condition D1 causes abrupt movement of the white charged particles injected into the cell. When the same driving waveform (D1) is applied to each sample, reflectivities of 32.1% for #1, 31.4% for #2, 27.9% for #3, and 63.4% for #4 are measured. From the experiment, we confirm that the driving condition D1 (1s of 3.5 V, 9s of 3.0 V) and ramp wave #4 in filtering are desirable for good reflectivity and response time. Our research is expected to contribute to the improvement of the filtering process and optimization of the driving waveform.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.745-747
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• 2001

This paper deals with the dynamic characteristics of flat core LOA. The LOA system was represented by the voltage equation of coil and the mechanical equation of motion. Also, driving system was simply composed voltage source inverter and generates square-wave. It is measured that dynamic characteristic vary as square-wave.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1247-1250
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• 2006

A new liquid crystal display (LCD) Data identified Time Extension (DiTEX) driving scheme with a high charged voltage is proposed. The different charged voltage owing to the differential charging time and various initial pixel-potential can be eliminated or diminished under this method. It is compatible with a 2-row inversion and can be realized into the commercial dual-sided gate circuits.