低功耗PMT 高压电源设计

针对目前光电倍增管(photomultiplier tube,PMT)高压电路存在的不足,研制专门用于14PIN的PMT高压底座。高压电源采用LT3580升压变换器,利用单端反激方式实现高压输出,12阶倍压整流给PMT各级提供分压,并列出设计原则和给出电源测试指标。结果表明:该方法是有效、可行的,能使电源体积和功耗明显减小。     

反激开关电源在洗衣机控制系统的应用

为了解决洗衣机控制器反激开关电源的两路输出电源带载差别较大时电压输出不稳的问题,采用负载端使用假负载、用PC817和TL431组成反馈回路并采用主极点补偿方式进行动态补偿,仿真及实测结果表明,当5 V输出满载12 V输出空载时,可以将12 V电压波动控制在10%范围内;当12 V满载5 V空载时,可以将5 V电压波动控制在2%范围内;两路带载情况下,双路输出电压波动可控制在2%范围内,实际应用表明,该方案可行有效。     

基于单端反激式本安电源的设计

针对煤矿井下易燃易爆的特殊环境,文章基于单端反激式变换器,设计了一种本质安全型开关电源,该电源结构简单,体积小,输入与输出电气隔离,具有多路本安输出端口,每路均设计过流过压保护。具体介绍其中一路输出18V/1A的设计。     

A dynamically reconfigurable NRTI switched-capacitor-based hybrid DC-DC converter suitable for embedded applications

In this paper, a dynamically reconfigurable, Non-overlap Rotational Time Interleaved (NRTI) switched capacitor (S-C) DC-DC converter is presented. Its S-C module is reconfigurable to generate three different fractions (viz., 1/3, 1/2 and 2/3) of its input supply (Vdd). This maintains good power efficiency while its output voltage gets adjusted over a large range. In addition, a load-current-sensing circuit is integrated within it to dynamically reconfigure the S-C module based on the required driving capability. This feature enables to extend load current range to higher limit and at the same time improves the power efficiency in low load current regime. The S-C module is integrated with a current control loop for load and line regulation.The proposed architecture is simulated in a 0.18 μm CMOS process using dual oxide transistors to demonstrate the efficacy of the proposed topology. The input supply voltage is 3.3 V and the regulated output range is 0.8-1.6 V. Total flying capacitance is 330 pF and the load capacitor value is 50 pF. For an output of 1.35 V, its power efficiency is maintained above 50% over a load current range of 4 -17.6 mA with a peak of 66% at 9 mA. Throughout this current range the output voltage ripple remains within 12 mV.     

一种用于光伏逆变器的反激式开关电源的设计

介绍了UC3843的工作特点,设计了一种采用UC3843控制芯片的多路输出反激式变换器为光伏逆变器的辅助电源。结合100～400V输入65W输出的样机试验,分析了电路的工作特点、变压器的设计要求,以及针对不同次级电流所需的次级电路结构设计。实验结果证明了设计的可行性,该反激式变换器具有效率高、稳定、动态响应快等优点。目前该电路已作为辅助电源,成功应用在一台光伏发电系统实验样机中。     

一种高精度时钟同步电路

本文提出了一种基于交错延迟单元和动态补偿电路的高精度时钟同步电路结构,HPSC,并 可用在对时钟要求较高的大规模分布网络中。此电路采用了基于SMD的粗调结构和动态补偿 电路的细调结构,可在两个时钟周期内完成粗调并在接下来三个时钟周期内完成细调,其误 差小于3.8 ps。本电路使用SMIC 0.13 μm 1P6M 工艺设计并实现,供电电压1.2 V。其输入 频率为200MHz-800MHz,占空比为20%-80%,有效面积 245μm×134μm,功耗为1.64 mW@500MHz     

光伏交错反激逆变器解耦控制方法的研究

交流光伏模块将光伏组件与微型逆变器集成为一体,构成一个可直接与电网或负载连接的光伏发电系统模块。微型逆变器独立控制每一个光伏组件,因此受到外部环境条件变化影响小,光伏电池的利用率优于其他光伏并网发电系统结构。首先,介绍了交错式反激逆变器的拓扑结构、工作原理以及并网控制技术;再对3种主动式功率解耦方式及控制方法进行了比较;仿真分析结果表明,3种功率解耦方式能够有效抑制二倍频功率扰动,提高了光伏电池板的效率,可延长电容寿命,但同时增加了设备的体积和成本,逆变效率也会相应下降,电路拓扑和控制都变得复杂。     

A simple control scheme for a single stage flyback LED driver

This study proposes a simple control scheme for using single‐stage flyback (SSF) converters in lighting source applications for LEDs. Among the advantages of the average current mode is an I/O current ripple that is only one‐half of the critical conduction mode (CRM). This condition helps extend the output capacitor lifetime while lowering the input EMI capacitance input EMI capacitance. The SSF converter proposed in this study operates in continuous conduction mode (CCM). In addition, two sample‐and‐hold (S/H) circuits are placed at the output voltage loop and feed‐forward path, respectively. Since these S/H circuits access the average output current and average feed‐forward voltage, the LED driver is unaffected by the 120‐Hz ripple noise, the total harmonic distortion (THD) is reduced, and the transient response of the output current is improved. Finally, the operation principles and design considerations of the studied LED driver are analyzed and discussed. A laboratory prototype is also designed and tested to verify the feasibility. Copyright © 2014 John Wiley & Sons, Ltd.     

一种新型大功率无损缓冲Buck变换器的研究

提出了一种优化的高速电机驱动电路。在传统的三相逆变电路前端加入多路交错并联的无损缓冲Buck变换器,实现了开关管的零电流开通(ZCS)、零电压关断(ZVS),从而解决了高开关频率下的损耗问题,提高了系统的效率及可靠性。同时多路无损缓冲电路共用一个二极管和电感,可有效减小变换器体积,提高功率密度。详细分析了该变换器的原理,并通过实验验证了分析和设计的正确性和可行性。     

高电压宽范围输入低电压输出的DC-DC辅助电源设计

高电压宽范围输入的DC-DC辅助电源技术是中高压、大容量电力电子变流系统的关键辅助技术。基于双管反激电路,本文设计了一个高电压宽范围300~2 500V输入,低电压24V输出的DC-DC辅助电源样机,并给出了电源详细的设计方案。相比传统辅助电源,设计的辅助电源启动支路在电源工作后可自动断开,实现了电源输入电压范围更宽目标;电源主电路由变压器隔离,控制、反馈电路由辅助绕组供电,确保了电源输入/输出高电压隔离;开关管驱动电路采用带耦合电感的脉冲变压器,满足了驱动信号高压隔离和同步驱动要求。此外,计算电源效率的结果表明,双管反激辅助电源更适合高电压输入场合。最后,进行了相关实验,结果验证了所设计的高电压宽范围输入的DC-DC辅助电源方案可行性和正确性。