不连续导通模式PSM PT控制开关变换器

脉冲跳周期调制（Pulse Skip Modulation,PSM）采用ON/OFF控制对输出电压进行调整,提高了开关变换器的轻载效率,但存在输出电压纹波大的缺点。文中结合开关变换器的脉冲序列调制（Pulse Train,PT）控制与PSM技术,提出了开关变换器的PSM PT控制技术,其降低了输出电压的纹波,并使PT控制开关变换器在空载时能稳定工作。     

设计实例designideas级联低压差稳压器、SMPS抑制纹波，保持效率

降压型SMPS（开关电源）能有效地将未稳压的电源转换为稳定的输出电压。但是．输出端会出现由开关而产生的有害纹波和输入瞬变。如将有噪声的电源加在RF功率放大器上．则会在广播频谱中注入寄生信号或调制噪声。模拟系统工程师与RF系统工程师都青睐传统的低噪声电源设计．它包括一个变压器、整流器和滤波器．后面是一个线性稳压器。一只低压差线性稳压器的低输出噪声和高PSRR（电源抑制比）可以确保干净的电源．不会造成对功率放大器输出的干扰。     

一种具有纹波抑制功能的斩波稳定放大器

基于SMIC 0.18 μm BCD工艺设计了一种低失调、低噪声的斩波稳定放大器。针对斩波调制技术引入输出纹波的问题,设计新型的乒乓结构陷波滤波器来抑制纹波,并采用复合路径多级放大器结构拓展了带宽。通过Spectre仿真验证,放大器增益带宽积为11.7 MHz,共模抑制比为145 dB,电源抑制比为126 dB。蒙特卡罗仿真结果表明,放大器失调电压分布的标准差为3.54 μV,输入噪声谱密度为32.1 nV/Hz,纹波抑制效果达83.1 dB。     

开关稳压器对低频纹波的抑制

本文应用平均值技术和描述函数法推导的开关稳压器小信号、低频线性平均值模型,分析了开关稳压器的频率特性及音频敏感度。采用校正网络来改善开关稳压器对低频纹波的抑制能力。合适的校正,可以使稳压器获得高增益、宽带宽的稳定工作状态。最后提供一个设计实例并进行了试验,理论分析与实验结果基本一致。     

基于状态机控制的降压型开关电容DC-DC转换器

介绍一种基于状态机控制的多种增益模式转换的控制方法,采用增益跳变和跳周期调制技术,控制增益模式的切换和开关频率,使输出电压稳定,并使系统有较高的转换效率。基于csmc0.5 μm CMOS工艺进行spectreverilog[JP]仿真,结果表明能准确控制3种增益的切换和开关频率的变化,并可输出约1.8 V的稳定电压,纹波＜20 mV,达到了预期目的。     

抑制电源波动影响的放大器

在需要高增益放大的场所,应用普通多级放大器往往对电源纹波要求很严。因为前级的集电极阻抗将电源纹波引导到后级的输入端,在后级的输出端以放大了的形式出现;而且级与级之间往往需要加强退耦,以免通过电源耦合引起自激;另外若要组成高开环增益的负反馈放大器的话,则由于多次级间耦合引起的相移的累积,往往使反馈环内对某一频率呈现360°相移而成为正反馈,造成不稳定。因此采用有一定抑制电源纹波影响和电源耦合能力的单级高增益放大器是比较合适的。电路介绍图1电路中,BG_1管作恒流源,基极由稳压管D_1再经R_2C_1滤波供电,以保证基极电流恒定不变。对于     

Intersil多种方案简化高性能电源设计

随着便携式设备、医疗设备以及通信设备等高性能应用对功能、性能和功耗的要求越来越高，电源设计已经成为整个系统的关键所在。“尤其在手机以及数码相机等在对电源纹波敏感的应用中，极低的电源纹波和最高的电源抑制比（PSRR）对提高图像质量十分必要，当这些应用有接近兆像素的分辨率时，这方面的要求会变得更加关键。”Intersil手持电源产品组市场经理Andrew Baker表示。     

闭环数字输入D类放大器实现卓越音质

传统的开环设计D类放大器对电源的纹波电流很敏感，会把耦合至音频段的纹波放大，产生音频干扰，因此通常需要精密设计、成本较高的低纹波电流电源。 德州仪器（TI）的数字输入20W立体声D类扬声放大器TAS5706采用闭环反馈技术，实现了出色的电源抑制比（PSRR），可补偿电源纹波对功放的影响，降低耦合至音频段的电源噪声，放宽了对电源的要求，在电压波动时也可保持恒定的输出功率，允许工程师设计更低成本的电源。     

基于PWM的D类音频功率放大器设计

提出了基于脉冲宽度调制（PWM）的音频功率放大器,利用较新颖的反馈结构改善了总谐波失真及噪音（THD＋N）与电源抑制比（PSRR）。该电路工作电源电压2．4V-5V,电路闭环增益可以实现6dB,12dB,18dB,24dB变化。采用CSMC05CMOS工艺设计,实现了高效率,低功耗,高保真。     

基于GSMC0.13μm工艺的低失调运算放大器设计

针对斩波调制导致的输出纹波和带宽受限的问题,采用复合路径结构,将运放分为高频低增益的主路径和低频高增益的辅助路径,主路径决定带宽,辅助路径决定失调,斩波调制位于辅助路径,解除了带宽限制;将Ping-pong自动调零与斩波调制相结合,减小了运放的失调和斩波调制导致的纹波;采用复合路径混合嵌套米勒补偿的方法来进行频率补偿,...     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NEXT GENERATION WIRELESS NETWORKS–ESPECIALLY THE USE OF MILLI-MICROWAVE BANDS

The global bandwidth shortage of wireless communications has motivated the exploration of the naillimeter wave （ram-wave） frequency spectrum for the next generation wireless communications. Recent advances in RF CMOS technology and high speed baseband signal processing technologies have enabled tile extensive research and development of turn-wave wireless communications. The multi gigabit per second data rate of ram-wave system will lead to applications in many important scenarios, such as WPAN, WLAN,back-haul for cellular system. And the frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND and even beyond 100 GHz. The propagation and the imitation of the RF circuits design in these frequency bands make the directional antennas be inevitable for mm-wave communications.