用于X波段行波管实验的脉冲电源研制

基于X波段行波管实验研究的需要,研制了行波管脉冲电源系统。该脉冲电源系统主要由阳极控制电源、慢波线电源、收集极电源、辅助电源和控制系统组成,其中关键在于阳极控制电源的研制。针对阳极控制电源的输出脉冲宽度变化大的特点,采用串联固态开关控制阳极电压。实验结果表明,该脉冲电源系统满足行波管实验研究的要求,在X波段行波管上实现了阳极脉冲电压脉宽在4μs~3000μs内连续可调。     

雪崩模式下的体结构GaAs光导开关

利用能量较低的脉冲激光二极管,在较高场强下触发GaAs光导开关,使其工作于雪崩模式,从而产生纳秒上升前沿的快脉冲电压。GaAs光导开关采用垂直体结构设计,芯片厚度为2 mm,电极形状分别为圆环和圆面,触发光脉冲从圆环穿过。快脉冲产生由同轴Blumlein脉冲形成线完成。对基于GaAs光导开关的同轴Blumlein脉冲线进行了模拟仿真和实验,当充电电压超过8 kV(40 kV/cm)后,开关开始了雪崩工作模式。当充电电压约为15 kV(75 kV/cm)时,在50 Ω负载上获得了约11 kV的脉冲电压,实验波形与仿真波形一致。对开关抖动进行了测试,其测试结果显示开关充电电压对抖动影响很大,随着开关偏压增加,开关抖动减小,开关获得了最小抖动约700 ps。     

MHz高压脉冲电源的研究

针对均匀放电、生物医疗等高频纳秒脉冲的应用需求,文中设计了一款基于射频MOSFET(Metal Oxide-Semiconductor Field Effect Transistor)的高重频高压脉冲电源。脉冲电源的控制信号由FPGA(Field Programmable Gate Array)提供,并通过光纤进行传输,经驱动芯片放大后同步触发每一级放电管。驱动芯片采用电源模块隔离供电的方式来提供不同的地电位。放电管采用RCD(Residual Current Device)吸收电路来改善开关时刻的瞬时工况。分析和研究了最后一级隔离电感对放电管电压波形、负载电压波形的影响,并对Marx电路做出了改进。实验结果表明,在1 kΩ纯阻性负载上,该电源可在1 MHz重复频率下输出上升沿为40 ns、半高宽为100 ns以及电压幅值为1.1 kV的纳秒脉冲。实验验证表明该电源能够在高频高压状态下稳定工作,满足设计要求。     

中功率二极管激光器脉冲驱动源研制

介绍了激光二极管脉冲驱动源的控制技术。采用单片机与可编程逻辑器件实现电流脉冲宽度脉冲频率的调节;通过误差反馈和驱动电压叠加实现脉冲恒流控制。运用两点校正法分段拟合MOSFET门极驱动电压与LD电流对应关系曲线,单片机依据曲线修正驱动电压值,对温度引起的LD电流变化进行补偿。实验结果表明采用此方式获得的电流脉冲波形优于采用PID控制方法的实验波形。该方法具有温度补偿功能,在温度变化时输出电流稳定。     

低温等离子体电源的设计及有机物降解研究

设计了一种高效纳秒(ns)级低温等离子脉冲电源,该电源主要由高压直流发生装置和脉冲形成单元两部分构成。分析了电源主电路工作原理,并在给定电路和负载参数下对电源主电路进行仿真,得出实验波形。在负载为400Ω时,输出最大电压幅值是25kV,ns级上升沿,脉冲重复频率1.2 kHz左右。在不同电压峰值和脉冲频率的情况下,考察对100mg/L对氯苯酚废水的处理效果。结果表明,对氯苯酚的降解率随着电压峰值和脉冲频率的增大不断升高。     

一种用于微波系统的输入电压控制电路

随着射频技术的不断发展,微波系统对功率密度、可靠性的重视程度不断提高。以氮化镓为基础的微波功率器件的应用取得了很大的进步,对微波系统的供电时序也提出了更高要求。根据微波系统对脉冲电压及电源时序控制的要求,设计了一种电压控制电路,实现直流输入电压的脉冲输出和上电、掉电时序的控制,并通过实验电路对设计原理进行了验证。     

基于移相控制的全固态高压脉冲电源设计

针对传统高压脉冲的功率器件耐压值有限,电压等级难以提升,效率低的缺陷,提出了一种基于移相控制技术的全固态高压脉冲电源。充电电源部分采用移相控制ZVS PWM全桥变换电路,减小开关损耗;高压脉冲电路以全固态IGBT作为主开关器件,不仅能提升电压等级,还能对脉冲宽度和频率进行调节。实验结果表明,输出脉冲电压最大值为10 kV,具有纳秒级陡峭前沿,且频率、脉宽均可调。     

三端双向负阻晶体管的模拟与实验

对双向负阻晶体管(BNRT)的三端特性进行了研究.根据器件模拟得到了器件内部电势和电场分布,解释了S型负阻特性产生机理.分别从模拟和实验得到了输出负阻曲线随控制极电压变化的情况,结果表明,随控制电压的增大,转折电压、转折电流和维持电压均增大.模拟结果和实验结果一致.BNRT的三端化实现,克服了两端应用的诸多缺点,大大增加了它在高速脉冲电路中的应用灵活性     

三端双向负阻晶体管的模拟与实验

对双向负阻晶体管(BNRT)的三端特性进行了研究.根据器件模拟得到了器件内部电势和电场分布,解释了S型负阻特性产生机理.分别从模拟和实验得到了输出负阻曲线随控制极电压变化的情况,结果表明,随控制电压的增大,转折电压、转折电流和维持电压均增大.模拟结果和实验结果一致.BNRT的三端化实现,克服了两端应用的诸多缺点,大大增加了它在高速脉冲电路中的应用灵活性.     

级联Blumlein型脉冲网络充电电源设计

各级Blumlein型脉冲形成网络充电电压的不一致是影响级联脉冲形成网络电压传输效率的因素之一,为了使级联网络的充电电压一致,设计了一种多路充电电源.每路电源由脉冲变压器,IGBT,初级储能电容组成,IGBT的同步触发使得每路电源同时对负载充电.实验结果表明各级网络的充电电压不一致性＜0.1％.     

Development on astable multivibrators using the combination of linear and non-linear materials as switching elements based on all optial method

In this communication we propose a method to implement an all-optical astable multivibrator using the non-linear material based switches and logic gates. The scheme can operate in real time. The delay time can achieve ps(pico-second). The pulse duration can be made very low and may cross the THz easily by selecting proper material and laser source.     

555定时器功能与应用特点

归纳了555定时器的功能,给出了一种易于记忆的简化模型,同时就其构成的无稳态触发器、单稳态触发器及双稳态触发器等应用电路的特点进行了探讨.     

单运放多谐振荡器

分析了一种由单运算放大器构成、电路中包含二个充放电回路的多谐振荡电路，并对振荡信号的波形和输出信号的振荡频率进行了讨论，得到了计算公式；对振荡电路进行了实验分析，测试结果说明了理论分析的正确性。     

A new fraction phase based low energy frequency calibration architecture along with an ultra low power VCO design

This paper presents the design and analysis of the architecture of a fraction phase based frequency calibration unit where the number of delay cells (that sense the fraction phase) have been reduced to zero. As no pre-calibration of the delay values are required, it becomes immune to process-voltage-temperature variation. Simulation results for frequency convergence have been provided for different target frequencies of an LC oscillator and for an accuracy of 400 ppm. The paper next presents the design and analysis of a voltage controlled oscillator in the form of an astable multivibrator that is similar to a single stage ring oscillator. A novel resistive tuning technique that occupies small chip area and provides less process variation and more matching has been proposed. Also, it has been shown that although the oscillator’s phase noise is worse than LC oscillator, the frequency convergence probability (when using the frequency calibration unit with 4 delay cells, due to the high jitter values) does not degrade significantly with the same calibration unit specifications. Hence successful integration of the oscillator with the calibration unit is possible with the advantage of having fully on-chip design with lower power consumption than that of LC oscillators. The oscillator and the calibration circuit have been designed in UMC 180 nm technology that together consume a current of 320µA (in simulation) from 1.6 V power supply. The designs have been targeted for implant telemetry in the 402–405 MHz band having the requirement of ultra low power consumption.

     

A new astable direct-coupled multivibrator

RC-coupled astable multivibrators which produce square waves have been described in many textbooks. In this letter a new astable multivibrator is introduced in which the collectors and the bases of both transistors are directly coupled to each other. The switching action takes place by means of a unique arrangement of the circuit elements. Triangular waves are produced at the transistor emitters.     

Integrated astable optical multivibrator using Mach-Zehnder interferometric optical switches

An integrated astable optical multivibrator has been analysed and demonstrated experimentally for the first time using a couple of Mach-Zehnder interferometric optical switches with crossed and straight electronic feedback. Fairly good agreement is found between experimental and analytical results.     

New constant-current controlled astable multivibrator for generating sawtooth and square waves

This article presents a now constant-current controlled astable multivibrator in which only one resistor and one capacitor is used, the other elements being transistors. The circuit consists of a constant-current source and the multivibrator itself. The multivibrator is specifically designed to have a simple three-stage direct-coupled transistor amplifier, with the output of the third stage fed back to the first stage and a capacitor connected across any two collectors. The switching action takes place by means of that capacitor. Linear sawtooth and square waves are generated simultaneously at the transistor collectors. Since only one resistor and one capacitor are required, this circuit is practical with IC fabrication.     

基于可编程控制器多谐振荡器的设计与分析

在数字电路中,常常需要一种不需外加触发脉冲就能够产生具有一定频率和幅度的矩形波电路,特别是要求频率和占空比可调的这种电路,它就是多谐振荡器.文章采用可编程控制器来设计完成该功能,它具有设计简单,完成方便,频率和占空比用软件就可调试,不需要对电路重新组装的特点.     

Current-controlled oscillator

A relaxation oscillator whose frequency is linearly related to an input control current is described. The circuit configuration is based on the emitter-coupled astable multivibrator. The linear frequency variation is obtained by incorporating a discriminator circuit and high-transconductance elements into the oscillator circuit. Experimental results obtained from a circuit constructed from monolithic transistor arrays indicate that frequency variation over two decades, with a linearity better than 0.1%, can be obtained.     

Integrated bistable optical multivibrator using electrooptically controlled directional coupler switches

An integrated bistable optical multivibrator based on two electro-optical directional coupler switches has been realised for the first time using Ti: LiNbO3 waveguides with two crossed feedback loops. The analysis and operation of the basic optical flip-flop are presented, and different feedback conditions and loops should provide other types of optical multivibrators, e.g. monostable and astable.