• Title/Summary/Keyword: Capacitance design

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Optimal Design of a-Si TFT Array for Minimization of Data-line Capacitance and Its Implementation (데이터 배선 용량 최소화를 위한 비정질 실리콘 박막 트렌지스터 배열의 최적화 설계와 구현)

  • Kim, C.W.;Yoon, J.K.;Kim, S.Y.;Kim, J.H.
    • Journal of Biomedical Engineering Research
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    • v.29 no.5
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    • pp.392-399
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    • 2008
  • Thin-film transistor (TFT) arrays for an x-ray detector require quite different design concept from that of the conventional active-matrix liquid crystal devices (AM-LCDs). In this paper anew design of TFT array which uses only SiNx for passivation layer is described to meet the detector performance and the product availability simultaneously. For the purpose of optimizing the design parameters of the TFT array, a Spice simulation was performed. As a result, some parameters, such as the TFT width, the data line capacitance, and the storage capacitance, were able to be fixed. The other parameters were decided within a permissible range of the TFT process especially the photolithography process and the wet etch process. Then we adapted the TFT array which had been produced by the proposed design to our prototype model (FDXD-1417 and evaluated it clinically by comparing with a commercial model (EPEX, Hologic, Beford, USA). The results say that our prototype model is slightly better than EPEX system in chest PA images. So we can prove the technical usefulness and the commercial values of the proposed TFT design.

Design & implementation of differential sensor using electrostatic capacitance method for detecting Ringer's solution exhaustion (링거액 소진 감지를 위한 정전용량방식의 차동센서 설계 및 제작)

  • Sim, Yo-Sub;Kim, Cheong-Worl
    • Journal of Sensor Science and Technology
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    • v.19 no.5
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    • pp.391-397
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    • 2010
  • This paper proposes a differential structure sensor for detecting Ringer's solution exhaustion, in which three C-type electrodes of 10 mm width are disposed on a ringer hose at a distance of 5 mm each other in the direction of Ringer's solution flow. In the center of middle electrode, two capacitances are formed at the proposed sensor. When ringer hose is filled with Ringer's solution, there is no difference between two capacitances. But capacitance difference exist under the Ringer's solution shortage, because the shortage causes the hose filled with air from the top position electrode. The capacitance difference got to maximum 1.81 pF, when air was filled between top and middle electrode and the last of hose was filled with 10 % dextrose injection Ringer's solution. The capacitance difference varied with hose-wraparound coverage of electrodes as well as the width of them. For hose-wraparound electrode coverage of 90 % and 70 %, the maximum capacitance difference was 1.81 pF and 1.56 pF, respectively. A differential charge amplifier converted the capacitance difference to electric signal, and minimized electrodes' adhering problem and external noise coupling problem.

Equivalent Parallel Capacitance Cancellation of Common Mode Chokes Using Negative Impedance Converter for Common Mode Noise Reduction

  • Dong, Guangdong;Zhang, Fanghua
    • Journal of Power Electronics
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    • v.19 no.5
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    • pp.1326-1335
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    • 2019
  • Common mode (CM) chokes are a crucial part in EMI filters for mitigating the electromagnetic interference (EMI) of switched-mode power supplies (SMPS) and for meeting electromagnetic compatibility standards. However, the parasitic capacitances of a CM choke deteriorate its high frequency filtering performance, which results in increases in the design cycle and cost of EMI filters. Therefore, this paper introduces a negative capacitance generated by a negative impedance converter (NIC) to cancel the influence of equivalent parallel capacitance (EPC). In this paper, based on a CM choke equivalent circuit, the EPCs of CM choke windings are accurately calculated by measuring their impedance. The negative capacitance is designed quantitatively and the EPC cancellation mechanisms are analyzed. The impedance of the CM choke in parallel with negative capacitances is tested and compared with the original CM choke using an impedance analyzer. Moreover, a CL type CM filter is added to a fabricated NIC prototype, and the insertion loss of the prototype is measured to verify the cancellation effect. The prototype is applied to a power converter to test the CM conducted noise. Both small signal and EMI measurement results show that the proposed technique can effectively cancel the EPCs and improve the CM filter's high frequency filtering performance.

Mutual Coupling Capacitance and Cross-talk in TFT-LCD

  • Yun, Young-Jun;Jung, Soon-Shin;Kim, Tae-Hyung;Roh, Won-Yeol;Choi, Jong-Sun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.71-72
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    • 2000
  • The design of large area thin film transistor liquid crystal displays (TFT-LCDs) requires consideration of cross-talks between the data lines and pixel electrodes. These limits are imposed by the mutual coupling capacitances present in a pixel. The mutual coupling capacitance causes a pixel voltage error. In this study, semi-empirical model, which is adopted from VLSI interconnection capacitance calculations, is used to calculate mutual coupling capacitances. With calculated mutual coupling capacitances and arbitrary given image pattern, the root mean square (RMS) voltage of pixel is calculated to see vertical cross-talk from the first to the last column. The information obtained this study can be utilized to design the larger area and finer image quality panel.

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Design and Fabrication Process Effects on Electrical Properties in High Capacitance Multilayer Ceramic Capacitor (고용량 적층 세라믹 커패시터에서 설계 및 제조공정에 따른 전기적 특성 평가)

  • Yoon, Jung-Rag;Woo, Byong-Chul;Lee, Heun-Young;Lee, Serk-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.2
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    • pp.118-123
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    • 2007
  • The purpose of this work was to investigate the design and fabrication process effects on electrical properties in high capacitance multilayer ceramic capacitor (MLCC) with nickel electrode. Dielectric breakdown voltage and insulation resistance value were decreased with increasing stack layer number, but dielectric constant and capacitance were increased. With increasing green sheet thickness, dielectric breakdown voltage, C-V and I-V properties were also increased. The major reasons of the effects were thought to be the defects generated extrinsically during fabrication process and interfacial reactions formed between nickel electrode and dielectric layer. These investigations clearly showed the influence of both green sheet thick ness and stack layer number on the electrical properties in fabricating the MLCC.

Simulations of Pixel Characteristics for Large Size and High Qualify TFT-LCD using a new sophisticated Capacitance Formulas (새로운 정전용량 계산식물 이용한 대면적 .고화질 TFT-LCD의 화소 특성 시뮬레이션)

  • 윤영준;정순신;김태형;박재우;최종선
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.613-616
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    • 1999
  • An active-matrix LCD using thin film transistors (TFTs)has been widely recognized as having potential for high-quality color flat-panel displays. Pixel-Design Array Simulation Tool (PDAST) was used to profoundly understand the gate signal distortion and pixel charging capability, which are the most critical limiting factors for high-quality TFT-LCDs. Since PDAST can simulate the gate data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the new set of capacitance models on the pixel operations can be effectively analyzed, The set of models which is adopted from VLSI interconnections calculate more precise capacitance. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

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Collocated Capacitance Sensor Design for Magnetic Bearing Control (자기베어링 제어용 동위형 축전 센서의 설계)

  • Shin, Dongwon;Kim, Jongwon
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.10
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    • pp.146-153
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    • 1996
  • This paper presents the development of a collocated capacitance sensor and its application to the controller design for magnetic bearing supported rotor systems. The main feature of the sensor is that it is made of a compact printed circuit board(PCB) so that it can be built into the actuator coil of the magnetic bearing unit. The singnal processing unit hax been also developed. The experi- mental results of the sensor performance evaluation on sensitivity, bandwidth and resolution are presented. Then, simulation study shows the advantages of the collocated sensor for magnetic bearings over the nonco- llocated sensor. Finally, the experimental result on the performance of the collocated sensor based contrl- ler for a magnetic bearing rotor system is presented.

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Effects of an Empirical Capacitance Models and Storage Capacitance Types on TFT-LCD Pixel Operations (실험적 정전용량 모델과 축적 용량 설계 방법에 따른 TFT-LCD 화소의 동작 특성)

  • Yun, Young-Jun;Jung, Soon-Shin;Park, Jae-Woo;Choi, Jong-Sun
    • Proceedings of the KIEE Conference
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    • 1999.07d
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    • pp.1750-1752
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    • 1999
  • An active-matrix liquid crystal display (LCD) using thin film transistors (TFTs) has been widely recognized as having potential for high-quality color flat-panel displays. Pixel-Design Array Simulation Tool (PDAST) was used to profoundly understand the gate signal distortion and pixel charging capability, which are the most critical limiting factors for high-quality TFT-LCDs. Since PDAST can simulate the sate, data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the new set of capacitance models on the pixel operations can be effectively analyzed. The set of models which is adopted from VLSI interconnections calculate more precise capacitance. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

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Design and Analysis of Electrical Properties of a Multilayer Ceramic Capacitor Module for DC-Link of Hybrid Electric Vehicles

  • Yoon, Jung-Rag;Moon, Bong Hwa;Lee, Heun Young;Jeong, Dae Yong;Rhie, Dong Hee
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.808-812
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    • 2013
  • Multilayer capacitors with high ripple current and high capacitance were manufactured. The electrical properties of these capacitors were characterized for potential application for DC-link capacitors in hybrid electric vehicle inverters. Internal electrode structures were designed to achieve high capacitance and reliability. A single multilayer capacitor showed $0.46{\mu}F/cm^3$ of capacitance, 0.65% of dielectric loss, and 1450 V to 1650 V of dielectric breakdown voltage depending on the design of the internal electrode. The capacitor module designed with several multilayer capacitors gave a total capacitance of $450{\mu}F$, which is enough for hybrid electric vehicles. In particular, an equivalent series resistance of $4.5m{\Omega}$ or less will result in 60 $A_{rms}$, thereby reaching the allowed ripple current for hybrid electric vehicles.

Capacitance Characteristics of a-Si:H Thin Film Transistor (비정질실리콘 박막트랜지스터의 캐패시턴스특성)

  • 정용호;이우선;김남오;이이수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1995.11a
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    • pp.118-121
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    • 1995
  • Fabrication and a new analytical expression for the capacitance characteristics of hydrogenerated amorphous silicon thin film transistors(a-Si:H TFTs) is presented and experimentally verified. The results show that the experimental capacitance characteristics are easily measeured. Measured transfer and DC output characteristic curves of a-Si:H TFT are similar to those of the standard MOSFET-IC. The capacitances on bias voltages are in good agreement with experimental data. This capacitance characteristics is suitable for incorporation into a circuit simulator and can be used for computer-aided design of a-Si thin film transistor integrated circuits.

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