一种机载DC/DC浪涌电流抑制电路的设计

为了满足EMC要求,通常需在机载二次DC/DC的输入端并联大容量电容,导致开机瞬间形成很大的浪涌电流,从而引起系统异常。常规的抑制方法是在输入端串联电感、NTC热敏电阻,或者串联MOS管并简单控制其缓慢开通。但这些方法存在输入电压振荡、高温时抑制失败,或者启动延时长且不能抑制重复快速浪涌等缺点。基于MOS管的密勒效应,设计了一种能够延长MOS管开通上升时间的电路,使电容电压上升速率变缓,从而抑制浪涌电流。仿真及验证结果表明,该电路具有启动延时仅有10 ms、可抑制最高60 Hz的重复快速上电浪涌、上电速率可调等优点。     

一种新的应用于开关电容DC/DC转换器的补偿电路

采用Chartered 0.35μm CMOS工艺,设计实现了输入电压范围2.7～5.5 V,负载电流高达200mA的降压式开关电容型DC/DC转换器.为了在整个输入电压和负载电流范围内稳定输出电压,并且提高输出电压精确度,在对开关电容转换器环路建模分析后,提出了一个新的应用于开关电容DC/DC转换器的频率补偿电路.该...     

移相控制ZVC PWM DC／DC全桥变换器的设计

就谐振软开关技术在DC／DC变换器中广泛应用,介绍了一种移相控制ZVC PWM DC／DC全桥变换器的设计方法,其包括功率开关管参数选取、主变压器设计、换流电感设计、缓冲电容选择及参数验算等。     

台商新品

低嗓音、小尺寸、高功效电源管理解决方案茂达电子(Anpec)推出APW7071/APW7072 PFM DC/DC升压组件系列,APW7071与APW7072频率最高可达1MHz,输出端仅需一颗0．1μF电容,使外部组件体绩最小化。而APW7071可操作在2．5V～6V输入电压范围之     

什么是DC放大器?

顾名思义,DC放大器就是指能放大直流信号的放大器,“DC”一词系英文单词Direct Curremt(直流)的缩写。众所周知,音乐信号的频率范围为2OH_z-20kH_z,为什么还要制造直流放大器呢? 实际上,制造直流放大器并不是因为人耳能听出直流,而是为了改善放大器的低频性能。功率放大器(或前置放大器)绝大多数均为多级放大,级与级之间涉及一个信号耦合的问题。常用的耦合方法有两种,一是电容耦合,二是直接耦合。电容耦合是在前一级的输出端与下一级的输入端之间插入一只电容端,因电容可起隔直流的作用,各级放大电路工作点非常稳定。但电容器会影响放大器的低频响应,产生较大的相移,电路施加负反馈以后有时还会出现低频自激振荡,即汽笛声。直接耦合方式则取消了放大电路的     

基于MATLAB的光伏离网系统仿真研究

介绍了单相光伏离网发电控制仿真系统,采用DC/DC和DC/AC两级拓扑结构对光伏离网系统进行了研究和设计。研究光伏组件、输入滤波电容和离网逆变器之间的耦合关系,通过双闭环控制策略,实现直流母线电压稳定以及逆变器稳定输出。在MATLAB仿真环境下,对所设计的光伏离网系统进行了仿真,仿真结果表明该方案和控制策略的正确性。     

基于MATLAB的光伏离网系统仿真研究

介绍了单相光伏离网发电控制仿真系统,采用DC/DC和DC/AC两级拓扑结构对光伏离网系统进行了研究和设计。研究光伏组件、输入滤波电容和离网逆变器之间的耦合关系,通过双闭环控制策略,实现直流母线电压稳定以及逆变器稳定输出。在MATLAB仿真环境下,对所设计的光伏离网系统进行了仿真,仿真结果表明该方案和控制策略的正确性。     

实现95%效率的开关电容倍压器

通过一只电阻为一只电容充电的效率为50％;因此,很多工程师都避免使用开关电容DC／DC转换器。但只当电容没有初始电压时,效率才是这个值。如果你打算切换一个已充电的电容,可以用接近100％的功率效率,将能量传送给输出端。     

具有电压检测功能的大功率设备软启动器设计

基于限制大功率设备启动时冲击电流的幅值、完善软启动器的各种功能、提高工作可靠性等目的,本轮文设计的软启动器利用运算放大器构成电压比较、运行自锁、延时等环节,通过采样整流滤波电容端电压的变化,实现交流输入电压检测、软启动电流切换、内部逻辑控制等功能,在不同的输入电压范围内,也能限制跃变电压的幅值,保证了软启动器工作的可靠性。该软启动器具有结构简单、动作可靠等优点,可广泛应用于电源输入端需进行AC/DC变换的大功率设备。     

控制电源上电和断电顺序的定序器

当某个设计使用了多个负载点DC/DC转换器,并需要一个特定的电源上电顺序时,将每个转换器的电源正常工作的输出连接到下一个转换器的使能输入端,就能得到所需的电压级联.     

Switched-Current Filters by Component Simulation

This paper discusses the synthesis of switched-current filters from continuous-time prototypes by the simulation of components, particularly capacitors and transconductors in Transconductance-C filters. The obtained structures implement discrete-time versions of the prototype circuit using bilinear or Euler formulas. All the proposed structures work with doubled effective sampling rate (sampling the input and updating the output at each phase), make strict use of voltage-sampling switches and naturally admit two-phases nonoverlapping clocks.     

薄膜电容在雷达发射电源中的应用

首先,分析了雷达发射电源输入整流滤波电路的特点;然后,对比分析了铝电解电容与薄膜电容在发射电源输入整流滤波电路中应用的优缺点;最后,通过实验对比了两种电容器在电路中的性能参数。实验部分通过完全替代和部分替代两种方式研究了薄膜电容替换铝电解电容后对发射电源输入整流滤波电路的影响,并分析了这两种方案与传统的铝电解电容的优缺点。实验结果表明:在发射电源输入整流滤波电路中,相比于铝电解电容,薄膜电容具有耐高压、损耗小、寿命长等特点。     

High Input Impedance Voltage-Mode Universal Biquadratic Filter with Three Inputs Using DDCCs

A new high input impedance voltage-mode universal biquadratic filter with three input terminals and five output terminals is presented. The proposed circuit uses three plus-type differential difference current conveyors, two grounded resistors and two grounded capacitors. The proposed circuit can realize all the standard filter functions: lowpass, bandpass, highpass, notch and allpass, without component matching conditions. The proposed circuit offers the features of high input impedance, low active and passive sensitivities and the use of only grounded resistors and capacitors.     

Transmission-line theory approach to solution of state equationsfor linear-lumped circuits

Linear-lumped circuits containing capacitors and/or inductors are described by differential equations. In computer-aided circuit analysis, these equations are discretized in time, thus being reduced to approximate formulas involving samples of voltages and currents. It is shown that these relations can be interpreted as exact equations for networks containing transmission lines. Hence, some features of the approximate formulas gain a clear physical interpretation. In particular, convergence and energy balance properties of the formulas become obvious, confirming advantages of the trapezoidal rule over all other formulas     

High Input Impedance Voltage-Mode Universal Biquadratic Filter with Three Inputs and Six Outputs Using Three DDCCs

A new high input impedance voltage-mode universal biquadratic filter with three input terminals and six output terminals is presented. The proposed circuit uses three plus-type differential difference current conveyors (DDCCs), three resistors, and two grounded capacitors. The proposed circuit can realize all the standard filter functions, namely, lowpass, bandpass, highpass, notch, and allpass, simultaneously, without component matching conditions. The proposed circuit still offers the features of high input impedance, using only grounded capacitors, and orthogonal controllability of resonance angular frequency and quality factor.     

High output impedance current-mode universal biquadratic filters with five inputs using multi-output CCIIs

Three current-mode universal biquadratic filters each with five input terminals and one output terminal are presented. The first proposed circuit uses three multi-output second-generation current conveyors, two grounded capacitors and three resistors. This circuit offers the following advantageous features: orthogonal controllability of resonance angular frequency and quality factor, high output impedance, the versatility to synthesize all standard filter types without component matching condition and using grounded capacitors. The second proposed circuit uses three multi-output second-generation current conveyors, two grounded capacitors and two resistors. This circuit offers the following advantageous features: using minimum passive components, high output impedance, the versatility to synthesize all standard filter types without component matching condition and using grounded capacitors. The third proposed circuit uses three multi-output second-generation current conveyors, two grounded capacitors and three grounded resistors. This circuit offers the following advantageous features: the versatility to synthesize all standard filter types, high output impedance and using only grounded passive components. Each of the proposed circuits can get five kinds of filter functions by using only one current input signal.     

High Input Impedance Voltage-Mode Universal Biquadratic Filter with One Input and Five Outputs Using Current Conveyors

A new high input impedance voltage-mode universal biquadratic filter with one input terminal and five output terminals is presented. The proposed circuit uses three differential voltage current conveyors (DVCCs), four resistors, and two grounded capacitors. The proposed circuit can realize all the standard filter functions—lowpass, bandpass, highpass, notch, and allpass—simultaneously, without changing the passive elements. The proposed circuit enjoys the features of high input impedance, orthogonal control of resonance angular frequency and quality factor, use of only grounded capacitors, and low active and passive sensitivities.     

Tunable frequency versatile filters implementation using minimum number of passive elements

Two new universal active current-mode filters are proposed, one topology of which is with three inputs and one output, the other prototype is with single input and three outputs counterpart. One proposed circuit employs two current conveyors, two grounded capacitors and two resistors, wherever the other proposed circuit employs two current conveyors, two grounded capacitors and two multi-input, multi-output Operational Transconductance Amplifiers(OTA) as variable resistor for tuning the cutoff frequency of realized filters. Without changing the passive elements, the proposed circuits employ features of multifunctional, convenient for integration, low sensitivities and simple in structure.     

Design formulas for biquad active filters using three operational amplifiers

A circuit configuration and its design formulas are presented for the realization of all the useful forms of a biquadratic voltage transfer function. The circuit employs three single-ended operational amplifiers, two capacitors, and at most eight resistors. With an additional resistor, it can realize any biquadratic voltage transfer function.     

Implementation of Chua's circuit using simulated inductance

In this study we describe how to build an inductorless version of the classic Chua's circuit. A suitable inductor for Chua's circuit is often hard to procure. The required inductor for the circuit is designed using simple circuit elements such as resistors, capacitors and operational amplifiers. The complete circuit can be implemented by using off-the-shelf components, and it can readily be integrated on a single chip. This design of Chua's circuit allows the original dynamics to be slowed down to just a few hertz, enabling implementation of sophisticated control schemes without severe time restrictions. Another novel feature of the circuit is that losses associated with capacitors due to leakages can easily be compensated by providing negative resistance using the same setup. The chaotic behaviour of the circuit is verified by PSpice and Multisim simulation and also by experimental study on a circuit breadboard. The results give excellent agreement with each other and with the results of previous investigators.