美国国家半导体PWM控制器

美国国家半导体公司（National Semiconductor Corporation）宣布推出一款新的脉冲宽度调制（PWM）降压控制器，其特点是采用美国国家半导体独有的仿电流模式（ECM）结构，确保输出电压时占空比可以降至最低，而开关频率可以高达1．5MHz。     

PFC与PWM控制器HA16141及其应用电路

HA16141是日立公司生产的PFC与PWM组合控制器 ,其PFC与PWM控制器的驱动峰值电流分别可达±1.5A和±1A。文中介绍了HA16141芯片的主要功能和电气特性。给出了HA16141与次边后置控制器HA16341在开关电源中的典型连接电路。     

一种高效的PWM开关电源控制新技术

研究了一款新型的脉宽调制(PWM)控制电路,该电路结构将传统的误差放大器,斜坡补偿和峰值电流检测电路转化为一个多输入的求和比较器来实现。从而使DC/DC转换结构变得简单,并且能够避免传统结构在PWM比较器输出的占空比大于50%时的稳定性问题。经HSpice仿真验证后得出该电路可适用于各种高精度DC/DC开关电源。     

IR3580等：PWM控制器

IR推出新一代电源管理总线（PMBus）驱动的多功能CHiL数字脉冲宽度调制（PWM）控制器和集成式PowlRstage解决方案。     

一种基于电流型PWM控制的放大器

提出一种基于电流型的PWM(脉宽调制)控制的放大器,该电流型放大器通过直接控制外电路电感电流峰值的大小,间接地控制PWM脉冲宽度。该放大器反馈电路中采用电压外环和电流内环,保证控制器的瞬态电流峰值跟随误差信号而变,并对电流采样电路优化设计使其具有一定的箝位功能。Cadence Spectre仿真结果表明:该电路增益为3 V/V,同相端最大输入信号电压为0.96 V,传输延迟仅为145.78 ns,仿真测试表明该电路完全达到设计指标要求。     

功放电源软启动电路的设计

大电流的音频功率放大器其电源部分通常附有软启动电路,以保证机器开启时不形成过大的冲击电流。然而,设计不当的软启动电路往往“矫枉过正”,会导致功放电路无法正常运行,如果因此而烧毁元件的话就更可惜了。笔者就这个音响设计环节中看似不起眼的软启动电路谈谈自己的看法,希望软启动电路不会成为功放制作中的“绊脚石”。     

单相同步降压型脉冲宽度调制（PWM）控制器系列

AP3585器件提供25A的连续电流,有助干简化为内存阵列和图形处理电元供电的分布式电源结构的设计。这款降压型控制器把10MHz误差放大器与6V／μs的速率集成起来,实现高转换器带宽及快速瞬态响应。该器件系列提供200kHz或300kHz的固定振荡器频率选择,确保达致最理想的集成效果,有效缩减电源尺寸及降低成本。     

脉冲宽度调制(PWM)器件的测试

本文介绍了PWM器件的出现、功能、结构和优点。同时，结合STS 2110B脉冲宽度调制器件测试系统，对PWM器件的测试原理和实现方法加以阐述和介绍。     

一种新型构成APF逆变主电路的PWM逆变器

采用有源电力滤波器（APF）巳成为谐波补偿的一个重要趋势，简要介绍了一种用于谐波补偿的构成APF的逆变主电路的PWM逆变器及具体电路，其功能是实现对控制电路发出的控制波形不失真的放大。     

脉冲宽度调制（PWM）器件的测试

PWM器件概述 1.PWM器件的出现 PWM器件是随着开关电源的发展和半导体集成技术的发展而出现的。 开关电源是一种高频电源变换电路,它采用开关器件来控制未经稳压的直流输入电源,配合相应的滤波线路,产生稳定的直流输出。输出直流电压的高低取决于开关器件工作的脉冲占空比。在早期,人们根据开关电源的工作原理,利用分立器件设计开关电源中的脉宽调     

工作在不同频率的脉宽调制器

许多应用需要脉宽调制(PWM)电路,如:电压调节器、功率控制、风扇速度控制等.图1所示电路利用三个运算放大器构成了PWM电路,由于运算放大器选择的灵活性,该方案能够满足各种应用的要求,例如,对于低功耗系统,可以选择微功耗运放;而高频运放则可用来实现高频PWM.图1电路还可用于产生三角波.     

Self-commutated auxiliary circuit ZVT PWM converters

This paper introduces a novel class of zero voltage transition (ZVT) DC/DC pulse-width modulation (PWM) converters that use a resonant inductance-capacitance (L-C) circuit connected to the auxiliary switch, which is termed a self-commutated auxiliary circuit. It provides a simple and reliable means of achieving zero-current conditions (ZCS) for auxiliary switch commutations under wide line and load ranges, without the inclusion of any kind of DC voltage source. Furthermore, this auxiliary circuit is placed in parallel with the main power converter, retaining the ZVT characteristics. The self-commutated auxiliary circuit ZVT PWM boost is analyzed, and its feasibility and reliability are confirmed by experimental results obtained from laboratory prototypes rated at 1 kW and 100 kHz.     

产生精确PWM波形的DDS电路

脉宽调制是一种调制或改变某个方波的简单方法.方波占空比基本形式是随输入信号变化的.占空比是指方波的高电平时间和低电平时间之比.     

Simple TRAPATT circuit model

It is shown that, by choosing the diode depletion capacitance and characteristic impedance of the transmission line to conform to a Gaussian-lowpass-filter model, it is possible to determine suitable diode package parameters for TRAPATT operation at various frequencies.     

Simple switched-capacitor decimation circuit

A simple SC decimation circuit is presented that simplifies the requirements for the preceding continuous-time antialiasing filter and permits the sampling frequency of the following SC filter to be reduced considerably. A practical example is given.     

Simple topologies of PWM AC-AC converters

This letter proposes a new family of simple topologies of PWM AC-AC converters with minimal switches. With extension from the basic DC-DC converters, a series of AC-AC converters such as buck, boost, buck-boost, Cuk, and isolated converters are obtained. By PWM duty ratio control, they become a "solid-state transformer" with a continuously variable turns ratio. All the proposed AC-AC converters in this paper employ only two switches. Compared to the existing circuits that use six switches or more, they can reduce cost and improve reliability. The operating principle and control method of the proposed topologies are presented. Analysis and simulation results are given using the Cuk AC-AC converter as an example. The analysis can be easily extended to other converters of the proposed family.     

Simple power control circuit

A simple circuit that gives a linear relation between input DC control voltage and an average load voltage is described. This circuit depends on a simple vector difference circuit based on inverse sine evaluation. The load voltage is found to be independent of the supply line voltage and of frequency fluctuations.     

New family of zero-current-switching PWM converters using a new zero-current-switching PWM auxiliary circuit

A new family of zero-current-switching (ZCS) pulsewidth-modulation (PWM) converters using a new ZCS-PWM auxiliary circuit is presented in this paper. The main switch and auxiliary switch operate at ZCS turn-on and turn-off, and the all-passive semiconductor devices in the ZCS-PWM converters operate at zero-voltage-switching (ZVS) turn-on and turn-off. Besides operating at constant frequency and reducing commutation losses, these new converters have no additional current stress and conduction loss in the main switch in comparison to the hard-switching converter counterpart. The PWM switch model and state-space averaging approach is used to estimate and examine the steady-state and dynamic character of the system. The new family of ZCS-PWM converters is suitable for high-power applications using insulated gate bipolar transistors (IGBTs). The principle of operation, theoretical analysis, and experimental results of the new ZCS-PWM boost converter, rated 1.6 kW and operating at 30 kHz, are provided in this paper to verify the performance of this new family of converters.     

Simple square-rooting circuit using OTAs

A method to implement a square-rooting circuit is described. The proposed circuit employs operational transconductance amplifiers (OTAs) as the only active elements. The implementation technique is based on an electronically variable resistor formed by the OTA, where the magnitude of the resistance is controlled by the output current, to provide the square-rooting function. The proposed scheme can operate with both a voltage input and a current input signal. The purpose of the circuit is emphasised in terms of simple configuration, high accuracy and low cost. Experimental results showing the circuit performance are presented.     

Simple CMOS transition accelerator circuit

A simple CMOS circuit whose input/output characteristics follow an 'antihysteresis' curve is presented. This curve is similar in shape to the input/output characteristics of a Schmitt trigger, but it is followed in the reverse direction. This circuit can be used as a transition accelerator.<>