三端集成稳压器扩流方法分析

以LM317K进行电流扩展为例介绍了三端集成稳压器的3种扩流方法,即晶体管扩流、电阻扩流和并联扩流。通过扩流解决了三端集成稳压器输出电流由于受限而不能满足设计要求的问题。给出了3种扩流方法的具体电路连接及原理分析。对LM317K设计的不同方案的扩流电路均使用Multisim V10软件进行了仿真,从仿真结果可以看出3种扩流方法的可行性和正确性。通过对3种扩流方法的分析和比较,给出了各自适用的场合和使用的注意事项。在实际应用中,可根据扩流的大小和使用的三端集成稳压器的型号来选择合适的扩流方法。     

基于STC89C52的程控恒流源的设计

高精度的程控恒流电源在仪器仪表、传感器技术和测试领域中有着广泛的应用.以往程控恒流源电路大都采用PwM脉冲方式,虽便于控制和调节,但精度难以保证,并且PWM方式的波形占空比调节范围有限,难以满足连续可调大电流的要求.本文介绍一种采用STC89C52单片机控制压控恒流源并通过扩流电路来实现恒流源程序控制的方案,其输出电流值可达2A.     

集成电路测试仪电源电路的仿真设计研究与应用

针对实验室某种集成电路测试仪使用中存在的因电源电路的设计不够完善、带负载能力差而存在死机或复位不正常的问题,在原有电路基础上,对电源电路进行改进设计,增加了扩流电路,并对改进电路用EDA仿真技术进行对比验证,并在实际应用中解决了问题.     

一种应用开关电容分压的电源电压检测电路

提出了一种基于标准CMOS工艺的电压检测(Voltage Detector, VD)电路,具有高集成度、低功耗、检测点多档位可调节的特点。开关电容(Switched Capacitor, SC)电路仅需一个低频时钟即可提供准确的电源分压,在低功耗应用中可以有效替代传统电阻分压。在3.3V电源电压的MCU应用中,电压检测电路仅消耗几百nA的电流,对时钟变化不敏感（低频时钟频率变化范围4 kHz~40 kHz）,并且响应时间在一个时钟周期内     

电容串联分压输出电路特性研究

为减少普通变压器瞬变高电压及电源电流对电路有源器件的冲击，详细介绍了一种电容串联分压输出电路的结构及其工作原理，利用实验的方法给出输入一输出电流与负载的关系及输出电压与负载的关系曲线图，通过关系曲线图对电容串联分压输出电路的特性进行深入的研究，结果表明：该电路没有普通变压器瞬变高电压对电路的冲击，也没有较大的电源电流对电路的冲击，这为初级有源器件的选用带来方便。     

直流稳压电源的研究与实现

在现代许多通信设备中都需要电源系统供电的质量与稳定性。介绍了直流电源的结构和工作原理,它主要由直流稳压扩流电路、软启动与过流保护电路、不间断供电电路、自动检测控制电路和报警电路组成,这种备用电源可以使交换机在断电状态下持续工作8个小时,保证通话不受外界电压干扰。该设计具有结构简单,成本低廉,工作性能稳定可靠的特点。     

雷达高功率电源的新型并联均流技术及应用

采用多台开关电源并联运行实现大功率电源系统输出是目前电源技术的发展方向之一。文中阐述了传统的并联均流电路,并提出了一种新型的并联均流方式,采用此并联均流方式,完成了48 V400 A高功率电源的实验。实验结果表明,并联均流效果理想,可满足高功率电源的设计要求。     

双路电源的主动均流电路系统研究

广泛使用的低成本电源管理芯片或直流电源模块通常并未集成输出均流控制功能,因此不能直接并联输出使用。而使用特殊的电源管理芯片或是额外的均流控制电路会提高电源电路的复杂程度,造成电路成本的提高。针对此应用场景,提出了一种具有主动均流功能的双路电源开关,作为负载开关或电源多路复用器应用于电路之中,利用开关电流的方法均分输出电流,在几乎不增加电路成本的同时对两路电源进行均流。阐述了所提双路电源开关的工作原理与参数设计方法,并通过仿真与实验证明了所提方法的正确性与可行性。     

含无伴电源电路的几种特殊解法探讨

电路中不与电阻串联的电压源和不与电阻并联的电流源称为无伴电源。当无伴电源出现在电路系统中时,电路分析变得比较复杂。最基本的做法是直接以支路电流或支路电压为电路变量,应用KCL,KVL和支路的伏安关系,通过列出独立方程求解;而这里则是从几种不同的新角度切入问题,对无伴电源电路的几种情况做了分析,并对几种特殊解法进行了探讨。     

同步控制的大功率机载相控阵雷达电源

针对某型相控阵雷达对阵面电源开关频率可控的要求，提出了一种带同步控制功能的高功率、高密度开关电源，该电源的开关频率可与雷达的PRF同步。介绍了该电源的电路组成，并着重对PS—ZVS—PWM全桥变换器和内部功率电路的并联方式及其均流问题进行了详细介绍，最后给出了主要技术参数和实验结果。实验结果表明，电路设计合理，能够满足相控阵雷达对高功率阵面电源频率可控的要求，提高机载雷达的性能。     

单位元波开关电容滤波器的新实现

本文给出了实现单位元波开关电容滤波器适配器的几个新电路。这些新适配器电路仪用一个单位增益器和一个两相时钟信号,而且电路特性对主寄生电容效应极不敏感。文中还分析了次寄生电容(包括电容器上极板对衬底的寄生电容和开关的寄生电容)对电路特性的影响。分析表明,整个次寄生电容效应表现为对反射系数的影响。通过调整一个电容,就可以把这种本来就很小的影响降至更小。另外,本文的电路还非常适合用于实现程控滤波器,可以有效地进行实时语声综合。最后,给出了一个五阶切比雪夫低通滤波器的例子。实验结果与理论相符。     

Novel realization of unit element wave switched capacitor filter

In this paper, some novel SC-adaptor circuits are presented to realize the unit element wave switched capacitor filter using two-phase clock signals. These circuits are insensitive to the bottom plate parasitic capacitances and request, only one unit-gain buffer to realize an, adaptor. The effects of top plate parasitic capacitances and switch parasitic capacitances on an adaptor are analyzed. The results show that the effects of those are small and can be reduced further by adjusting only one of the capacitances. These circuits are adaptable for realizing programmable filters and very useful to the LPC real-time speech synthesis. As an example, a 5th order unit element low-pass filter is given. The experimental results are in excellent agreement with the theory.     

Generation of Generalized Impedance Converter Circuits Using NAM Expansion

The generation of the voltage generalized impedance converter (VGIC) circuits using a nodal admittance matrix (NAM) expansion is given in detail. Thirty-two equivalent circuits using current conveyors (CCII) or inverting current conveyors (ICCII) or a combination of both are generated. The reported circuits are suitable for realizing inductors or frequency dependent negative resistors (FDNR) using grounded passive elements. Similarly the generation of the current generalized impedance converter (CGIC) circuits published recently is reexamined and this resulted in 16 more new CGIC circuits using an alternative NAM expansion. Modification of two of the generated circuits to realize a floating inductor or floating FDNR is also given together with Spice simulation results.     

半导体激光器驱动电源的设计

本文的主要工作以数字式大功率半导体激光器驱动电源设计展开,主要是实现能够给半导体激光器提供最大输出40A、输出电压在2V~10V的恒流源。基于驱动电源的技术要求,设计了驱动电路主回路、保护电路、温控单元等数字式大功率半导体激光器驱动电源的主要部分。     

A Square-Root Domain Differentiator Circuit

Companding circuits are very useful blocks for realizing low-voltage, high-frequency analog systems. They are implemented using the translinear principle and the quadratic/exponential I-V characteristic of MOS/BJT transistor. In this paper, a Square-Root Domain differentiator is proposed. It is constructed from an appropriate input stage that converts the input current into a compressed voltage at a capacitor's node, and simultaneously senses the capacitor's current. The overall configuration of the differentiator also includes a current geometric-mean circuit and a multiplier, both based on a translinear loop. An attractive characteristic of the proposed circuits is their immunity to body effect. HSPICE simulation results were used for evaluating the behaviour of the differentiator.     

基于单个CCCCTA接地回转器的系统综合

为综合基于CCCCTA的接地回转器,根据CCCCTA的零-镜模型和接地回转器的节点导纳矩阵,利用节点导纳矩阵扩展法,我们实现了4个相互等效的接地回转器。导出的回转器具有两个特点,一个是通过调节CCCCTA的偏置电流,可以电控调节回转器的参数; 另一个特点是电路仅使用单个CCCCTA。作为一个例子,通过使用导出的回转器之一,我们实现了一个极点频率为1.274MHz、品质因素为4的带通滤波器。计算机仿真证明所导出的电路正确有效。     

三值动态和静态广义时序机理论

该文在三值电路三要素理论的基础上提出了三值动态和静态广义时序机理论。首先找出三值状态图和电路方程间的关系,该关系既适用于静态电路,又适用于动态电路。对静态电路文中推导出各型三值触发器完整特性方程,它描述了触发器全时刻的行为,用以代替常规特性方程,使三值同步和异步时序电路统一。对动态电路该文用电容代替触发器存储三值信息,实现三值动态时序电路(特别是三值同步动态时序电路,属于非触发器式的时序电路)。因动态电路和静态电路主要差别是负载行为,故此可以在三值电路三要素理论和广义时序机理论下统一三值动态和静态,同步和异步时序电路。     

Novel cascadable current-mode first order all-pass sections

This paper presents some new current mode first order all-pass sections with grounded components employing a modified current conveyor. The new circuits are ideal for current-mode cascading by possessing high output impedance. As an application of the circuits, a new quadrature oscillator is also given. The theory is validated through PSPICE simulation using 0.5μ CMOS parameters.     

The higher order modal characteristics of circular-rectangularcoaxial waveguides

A rigorous analysis combining the orthogonal expansion method and Galerkin method for the higher order eigenmodes in a circular-rectangular (C-R) waveguide is presented in this paper. The Bessel-Fourier series is employed to merge the circular and rectangular coordinate systems used in the analysis. The cutoff frequencies of the higher order modes are determined with the singular value decomposition (SVD) technique. The computed results are in excellent agreement with results obtained using the finite element method. Because of its analytic form, the solution will be useful in the rigorous analysis of many practical microwave components and circuits     

Perturbation-Based Fourier Series Analysis of Transistor Amplifier

A perturbation-based Fourier series model is proposed to approximate the nonlinear distortion in weakly nonlinear circuits. This general model is applicable to any set of multi-variable state equations that completely describe a nonlinear circuit. This model is applied to a common emitter amplifier circuit wherein the transistor is represented by Ebers–Moll nonlinear current equations. Appropriate state variables are defined, then the linear and nonlinear parts of the Ebers–Moll current equations are separated, and a small perturbation parameter is incorporated into the nonlinear part. Now these current equations are incorporated into the set of KCL, KVL equations defined for the circuit and the state variables are perturbatively expanded. Hence, multi-variable state equations are obtained from these equations. The state variables are approximated up to first order through Fourier series expansion, as described in the proposed model. The main advantage of the proposed model is that it is simple and straightforward approach to analyze weakly nonlinear circuits, as it involves matrix computations and the calculations of exponential Fourier coefficients.