KA7526功率因数校正控制器及其应用

KA7526是FairchildSemicondu-ctor公司生产的一种简单高效的功率因数校正控制器。利用它可以设计出最优化的低功耗、高功率密度的电子镇流器,而且占用线路板的空间很小。由于KA7526内含RC滤波器,因此,用它设计电子镇流器不需要外部RC滤波器。KA7526中的误差放大器和乘法器的内部门限可在电路出现过载时打开输出以进行限流操作,同时也可以防止负载断开。由于这种输出驱动限制电路限制了功率MOSFET门驱动电路在电源电压中点处的过载,因而极大地提高了整个系统的可靠性。图1统的可靠性。主要特点KA7526型PFC控制器的主要特点如下:(1)…     

基于KA1M0880的多路高效AC/DC电路

KA1M0880是三星公司生产的一款高效、高稳定性、外围元件最少高压PWM系列电路，它内含高压MOS场效应晶体管和完善的内部保护电路。文中描述了KA1M0880的功能及电气参数，同时分析了使用该电路做前置稳压并配合CW4962设计的多路高效AC/DC的特点，最后结合实际使用给出了具体的电路设计图。     

一种简易实用的抢答电路

<正> 本文介绍一种简单实用的抢答电路,它由按钮开关、继电器和彩色灯泡组成(见附图)。该电路由交流220V市电供电,可供四个小组使用。它具有电路元件少、故障率低、工作可靠等特点。 该抢答电路的工作原理如下:抢答开始后,如果第一小组抢先按下按钮开关SB1,则继电器KA1线图通电,其常开触点KA1-4闭合,指示灯H1亮。与此同时,其常闭触点KA1-1、KA1-2、KA1-3都断开,使继电器KA2、KA3、KA4回路断开。这时其它小组再按按钮开关SB2、SB3、SB4,相应的继电器KA2、KA3、KA4也不能吸合,指示灯H2、H3、H4均不亮,起到     

基于KA3525的单片机辅助PWM控制电源电路

根据KA3525的应用特点,设计了一种基于该电流型PWM控制芯片和单片机控制实现输出电压可调的稳压电源电路.本文主要介绍了它的主电路、调控电路以及调控电路所包含的控制电路、稳压电路和保护电路,并介绍了它们的实现原理与方法.     

电话机振铃电路的改进

<正> 在电子技术日益发达的今天,电子电话机新品层出不穷,其电子振铃电路也越来越变得新颖,振铃声悦耳动听。相比之下,老式电话机的机械振铃电路已陈旧过时,振铃声生硬呆板。其实,只要拆除原机械振铃,改用电子振铃电路元件,再稍加改动,即可成为电子振铃电路。这种改制方法非常方便,成本也较低,有兴趣的读者不妨一试。 一、用KA2411制作的振铃电路 KA2411是比较早期的电话机专用电子振铃集成电路,其内部电路主要包括振铃信号发生器和振铃信号放大器。如图1所示,将原机振铃线圈拆除,两根引线接入aa′端,振钤信号经过3kΩ电阻限流,再经过由四只二极管构成的全波整流器整流、100μF电容滤波和6V稳压管稳压后,送KA2411①脚作电源。每当外线振铃信号到来,KA2411便由此电源驱动产生本机电子振铃信号,井由⑧脚输送到扬声     

春兰KFD70L空调故障检修

故障现象:能制冷,无法制热。分析检修:能制冷无法制热,重点检查制热相关电路(相关电路如图1、图2、图3、图4所示)。正常时按制热按钮S2、集成块IC2第(?)脚输出高电平,三极管VT3饱和导通,制热控制继电器K3受电吸合,其常开接点K3-1闭合,制热继电器KA3受电吸合,其常开接点KA3-1接通,制热交流接触器KM受电吸合,三对常开主接点接通三组六只电加热管EH380V电源,电加热管EH受电发热。同时K3-2常开接点接通风扇控制继电器KA1(低速)或KA2(高速),KA1或     

三星MAX-560V组合音响原理与检修

三星MAX-560V型组合音响光盘伺服系统和数字信号处理系统是由RF预放／伺服信号处理器KA9220、伺服信号驱动放大器KA9258、数字信号处理器(DSP)KS9283组成。伺服信号处理电路KA9229完成对误差信号进行数字处理任务，同时也处理光盘RF数字信息：KA9258芯片中设有4个独立的驱动放大器，对KA9220处理后的聚焦线圈、循迹线圈、进给电机、主轴电机的控制信号进行功率放大，分别驱动聚焦线圈、循迹线圈、主轴电机和加载电机。     

春兰KFD70L空调故障检修

故障现象:能制冷,无法制热. 分析检修:能制冷无法制热,重点检查制热相关电路(相关电路如图1、图2、图3、图4所示).正常时按制热按钮S2、集成块IC2第(13)脚输出高电平,三极管VT3饱和导通,制热控制继电器K3受电吸合,其常开接点K3-1闭合,制热继电器KA3受电吸合,其常开接点KA3-1接通,制热交流接触器KM受电吸合,三对常开主接点接通三组六只电加热管EH380V电源,电加热管EH受电发热.同时K3-2常开接点接通风扇控制继电器KA1(低速)或KA2(高速),KA1或KA2受电吸合,同时其触片KA1-1、KA1-2或KA-1、KA2-2吸合,风扇M1或M2启动将电热管EH热量吹出,实现制热.制热状态下测IC2第(13)脚输出为高电平,正常.继电器K3已吸合,但K3-1、K3-2常开接点均未接通.判定继电器K3接点卡涩损坏,更换继电器K3后制热恢复正常.     

电子信箱

吉林任贤问厦新DVD-8350型DVD视盘机开关电源中有一只型号为KA5L0380R的电源块,无法找到其任何资料,请介绍其各引脚功能。答KA5L0380R内部含有时钟、5V稳压、限流和逻辑等电路,具有过压、过流、过热和欠压保护功能,是一款性能优良的新型电源电路,采用4引脚TO-220F封装结构。其1     

基于CD5151的微型黑白电视机原理及故障分析

目前很多院校电子专业都安排了组装5.5寸黑白电视机的实习内容,各厂家所提供的实习套件,电路原理基本相同,都是以集成电路KA2915、D2915、CD5151为核心,辅以其它外围电路构成,三种核心集成片引脚完全兼容。     

有源高功率因数电子镇流器

为了提高电子整流器的功率因数,讨论了高性能电子镇流器系统必须具备的电路结构和功率因数校正电路(PFC)的基本原理。介绍了一种以L6561为功率因数校正控制器的有源高功率因数电子镇流器,说明该镇流器的电路组成及L6561的主要特点,并给出详细的电路原理图及主要元器件的选型。     

A novel single-stage push-pull electronic ballast with high inputpower factor

A novel single-stage push-pull electronic ballast with high input power factor is presented in this paper. The proposed electronic ballast combines the front-end power-factor corrector and push-pull converter into a single-stage power converter. Compared to the single-stage class-D electronic ballast, the proposed circuit does not require an isolated driver. The control of the circuit is easier and the cost less. The circuit of the ballast is analyzed and the design guidelines are listed. The experimental results verify the theoretical derivation     

A Novel Constant Power Control Circuit for HID Electronic Ballast

This paper presents a constant power control circuit for a three-stage high-intensity discharge (HID) electronic ballast. The three-stage electronic ballast is composed of a boost pre-regulator to achieve a high power factor, a DC/DC buck converter to regulate lamp current with constant lamp power, and a full-bridge inverter to drive the HID lamp with a low-frequency ac squarewave current. The buck converter operating in current mode utilizes current sense level-shift technique to achieve constant power output. The proposed constant power control circuit is easily designed and implemented for the three-stage HID electronic ballast. Finally, a laboratory prototype of a 70 W HID electronic ballast is implemented. The measured results show that the proposed ballast can be applied for various HID lamps with low lamp power variation (less than 0.6%).     

250W高压钠灯电子镇流器的研究

为满足人们对绿色照明的要求,该文设计了节能、高功率因数及总谐波失真低的高压钠灯电子镇流器来替代传统的电感式镇流器,采用有源功率因数校正、恒功率控制、低频方波驱动的三级式结构的电路设计,并搭建了样机,实现了160V～265V宽电压输入,功率因数PF≥0.99,总谐波畸变因数THD≤9．1％,电路可靠工作,通过了电磁兼容传导干扰测试。     

一种用于投影光源的高性能电子镇流器

提出了一种用于投影光源的高性能电子镇流器.主电路采用无源无损的缓冲电路,减小了由于续流二极管反向恢复所引起的开通损耗,提高了镇流器的效率.以数字控制器为核心,结合模拟方式的PWM控制,实现了恒功率控制.分析了镇流器的工作原理并给出了实验结果,实验结果表明该镇流器具有电路简单、可靠性高的优点,实验样机的效率达到了94%.     

一种E类驱动单级式电子镇流器的仿真研究

提出了一种E类驱动结构的谐振式电子镇流器,将E类结构和buck-boost功率因数校正结构整合成一种单级式电子镇流器。由于E类驱动式的谐振电路只需一个开关管,经过整合后的电路也只需一个控制电路和一个开关管,进一步降低了镇流器的成本提高了效率。文章分析了E类镇流器电路工作在最佳情况下的工作状态,仿真采用脉宽调制控制电路工作。     

Single switch unity-power-factor dimmable fluorescent lamp ballastcircuit

The authors propose an electronic ballast circuit which is capable of achieving high power factor, high efficiency, dimming control, and freedom from lamp flickering. All these features are accomplished with a single-switch power circuit, and a low-cost control circuit. Experimental results are given     

Single-stage electronic ballast with high-power factor

This article proposes a single-stage electronic ballast circuit with high-power factor. The proposed circuit was derived by sharing the switches of the power factor correction (PFC) and the half-bridge LCC resonant inverter. This integration of switches forms the proposed single-stage electronic ballast, which provides an almost unity power factor and a ripple-free input current by using a coupled inductor without increasing the voltage stress. In addition, it realises zero-voltage-switching (ZVS) by employing the self-oscillation technique. The saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. Therefore, the proposed single-stage ballast has the advantage of high-power factor, high efficiency, low cost and high reliability. Steady-state analysis of the PFC and the half-bridge LCC resonant inverter are described. The results of experiments performed using a 30 W fluorescent lamp are also presented to confirm the performance of the proposed ballast.     

Acoustic-Resonance-Free High-Frequency Electronic Ballast for Metal Halide Lamps

To avoid the acoustic resonance on operating metal halide lamps, an autofrequency-searching method is implemented on the high-frequency electronic ballast. The proposed method allows the use of a high-frequency electronic ballast, making the ballast able to adjust the operating frequency automatically as soon as the acoustic resonance is detected and, consequently, to locate it at a stable frequency. The electronic ballast achieves a high efficiency and a high power density through the employment of a high-frequency resonant inverter with an embedded buck-boost converter for power-factor correction and lamp power regulation. The control strategy is realized by a microprocessor along with the acoustic-resonance detection circuit. The operation of autofrequency searching is illustrated by the experiments on an electronic ballast designed for 70-W metal halide lamps.      

数字控制金卤灯电子镇流器样机设计

本文基于金卤灯电子镇流器数字控制策略分析的基础上,对其电路拓扑的主电路和控制电路进行设计,即对PFC、DC/DC、DC/AC三级结构的主电路及控制电路模型和参数进行选择、设计,并研制了一台高功率因数低频方波输出的数字控制金卤灯电子镇流器,通过对实验结果分析验证了所提出的数字控制方案是可行的。