High-voltage portable pulsed power supply fed by low voltage source

This article proposes a new structure of voltage multiplier for portable pulsed power applications. In this configuration, which is based on capacitor-diode voltage multiplier, the capacitors are charged by low AC input voltage and discharge through the load in series during pulse generation mode. The proposed topology is achieved by integrating of solid-state switches with conventional voltage multiplier, which can increase the low input voltage step by step and generate high-voltage high-frequency pulsed power across the load. After some discussion, simulations and experimental results are provided to verify the effectiveness of the proposed topology.     

静电激励放大器的设计

静电激励放大器是电容传声器的性能测量、分析及生产过程中的检验不可缺少的设备。这里简要介绍一种这样设备的设计方案及电路设计，并进行了电路分析。     

Characteristics of pentacene organic thin film transistor with top gate and bottom contact

High performance pentacene organic thin film transistors (OTFT) were designed and fabricated using SiO₂ deposited by electron beam evaporation as gate dielectric material. Pentacene thin films were prepared on glass substrate with S--D electrode pattern made from ITO by means of thermal evaporation through self-organized process. The threshold voltage V_TH was --2.75± 0.1V in 0---50V range, and that subthreshold slopes were 0.42± 0.05V/dec. The field-effect mobility (μ_EF) of OTFT device increased with the increase of V_DS, but the μ_EF of OTFT device increased and then decreased with increased V_GS when V_DS was kept constant. When V_DS was --50V, on/off current ratio was 0.48× 10⁵ and subthreshold slope was 0.44V/dec. The μ_EF was 1.10cm²/(V.s), threshold voltage was --2.71V for the OTFT device.     

高血压性脑出血再发生因素的Logistic分析

根据问题的特点 ,选择 Logistic判别模型 ,并借鉴普通线性回归的逐步向前法 ,用似然比统计量 ( Deviance)来筛选自变量 (因素 ) .结果显示 :在 1 1个因素中 ,有 3个是作用显著的 ,而其中舒张压值极为重要 .为降低再出血率 ,将其控制在 85 mm Hg以下是有效而可行的     

Quadrature Oscillators with Grounded Capacitors and Resistors Using FDCCIIs

Two current‐mode and/or voltage‐mode quadrature oscillator circuits each using one fully‐differential second‐generation current conveyor (FDCCII), two grounded capacitors, and two (or three) grounded resistors are presented. In the proposed circuits, the current‐mode quadrature signals have the advantage of high‐output impedance. The oscillation conditions and oscillation frequencies are orthogonally (or independently) controllable. The current‐mode and voltage‐mode quadrature signals can be simultaneously obtained from the second proposed circuit. The use of only grounded capacitors and resistors makes the proposed circuits ideal for integrated circuit implementation. Simulation results are also included.     

敏感元件在有线电视器件中的应用

阐述敏感元件的基本概念及其在有线电视网络器件中的几种典型应用,首先介绍敏感材料的基本类型和今后的发展趋势,然后详细介绍目前比较典型的几种敏感元件在开关稳压电源、Cable Modem、双向放大器、彩电消磁、程控交换机、光工作站中的应用。     

一种适用于单片集成DC-DC变换器的带隙基准电路

文章设计了一种用于单片集成DC-DC变换器的高性能带隙基准电压电路。当温度从-40℃～125℃变化时,温度系数为23ppm/k,其电源抑制比(PSRR)为54dB。当输入电压在2.5V～6V变化时,基准电压的变化范围为±0.055mV。     

低压差电压调整器中热保护电路的设计

针对常见电压调整器芯片由于热保护电路高温端性能的限制,导致调整器在较高工作温度下输出电压稳定性变坏的缺点,提出一种可用于低压差电压调整器的高性能热保护电路的设计。通过改进热保护电路的电路结构及版图设计,在保证热保护电路的关断精度达到±0.5℃的同时,改善了电压调整器高温段的输出电压稳定性。用Spectre对电路进行仿真的结果表明,采用该热保护电路的电压调整器在0℃～150℃范围内的输出电压精度保持在0.5%之内,输出电压的温漂达17.5ppm/℃。此外,设计的热保护电路结构简单,占用芯片面积小,可在双极型或BCD(BipolarCMOSDMOS)工艺下实现,应用于多种电源管理芯片设计中。     

有源光电式电流互感器的研究

光电式电流互感器已经成为国内外研究的热点,其中Rogowski线圈、高压侧电路的供电电源是目前研究工作的重点。在此介绍了有源光电式电流互感器基本原理,叙述了Rogowski线圈采样原理。Rogowski线圈的性能易受外界磁场和环境温度等因素的影响,对Rogowski线圈的制作提出了改进。有源光电式电流互感器高压侧供能问题仍未得到很好的解决,对母线电流取能、电容电流取能、激光供能、太阳能供电几种供能方式进行了研究分析。     

电解质对高压(160 V)液体钽电容器电性能的影响

研究了有机物对液钽电容器工作电解质闪火电压及电导率的影响。试验表明,适当的有机物加入工作电解质中,可以吸附在Ta2O5介质膜表面,减少阳极界面处阴离子的有效浓度,使工作电解质闪火电压适当提高。利用所研制的工作电解质浸渍装配成160 V/47μF的液钽电容器,经1 000 h高温负荷实验,测试结果表明电容器电性能良好。