Matlab在负反馈放大电路分析中的应用

采用方框图分析法,对电压负反馈放大电路进行了分析。经对闭环和开环状态下的微变等效电路分别列写节点方程,并利用Matlab软件,编写程序,求解电路方程。运行结果表明,开环与闭环增益满足反馈放大器中的基本关系式,同时,引入负反馈后稳定性得以提高,输入、输出电阻减小,与负反馈对放大器性能影响中的基本理论相一致。     

Multi-Input Floating Gate Differential Amplifier and Application to Intelligent Sensors

Multi-input floating gate differential amplifier (FGDA) is proposed which can perform any convolution operation with differential structure and feedback loop. All operations are in the voltage mode. Only one terminal is required for the negative feedback which can suppress distortions due to mismatches of active elements. Possible applications include intelligent image sensor, where fully parallel DCT operation can be performed. A prototype chip is fabricated which is functional. A preliminary test result is reported.     

A Feedback Receive Amplifier for Optical Transmission Systems

We consider the design and implementation of a lownoise feedback receive amplifier for use in optical communication systems. The feedback amplifier configuration is advantageous in that it offers a wide bandwidth with good signal to noise ratio.     

Differential Hot Electron Injection in an Adaptive Floating Gate Comparator

We introduce differential-mode hot electron injection for adapting and storing analog nonvolatile signed state variables. This approach is compatible with modern digital CMOS technologies and is readily extended to novel circuit applications. We highlight advantages of the technique by applying it to the design of an adaptive floating gate comparator (AFGC). This is the first use of this technique for adaptation in a nonlinear circuit. The AFGC computes appropriate voltages for locally adapting the input floating gate nodes to cancel offsets. The technique is amenable to both local and nonlocal adaptation which allows greater design flexibility. The AFGC has been fabricated in a commercially available 0.35 μm CMOS process. We experimentally demonstrate more than two orders of magnitude reduction in offset voltage: the mean offset is reduced by 416× relative to chips direct from the foundry and by 202× relative to UV-irradiated chips. We consider both static and dynamic adaptation and demonstrate that the the accuracy of dynamic offset cancellation is approximately two orders of magnitude better than static adaptation. In the presence of observed 8% injection mismatch, the AFGC robustly converges to within 728 μV of the desired input offset (mean offset −109 μV, standard deviation 379 μV). Adaptation occurs within milliseconds, with charge retention for more than one month, and variation of offset error with temperature of −15 μV/°C.     

Differential Hot Electron Injection in an Adaptive Floating Gate Comparator

We introduce differential-mode hot electron injection for adapting and storing analog nonvolatile signed state variables. This approach is compatible with modern digital CMOS technologies and is readily extended to novel circuit applications. We highlight advantages of the technique by applying it to the design of an adaptive floating gate comparator (AFGC). This is the first use of this technique for adaptation in a nonlinear circuit. The AFGC computes appropriate voltages for locally adapting the input floating gate nodes to cancel offsets. The technique is amenable to both local and nonlocal adaptation which allows greater design flexibility.The AFGC has been fabricated in a commercially available 0.35 μm CMOS process. We experimentally demonstrate more than two orders of magnitude reduction in offset voltage: the mean offset is reduced by 416X relative to chips direct from the foundry and by 202X relative to UV-irradiated chips. We consider both static and dynamic adaptation and demonstrate that the the accuracy of dynamic offset cancellation is approximately two orders of magnitude better than static adaptation. In the presence of observed 8% injection mismatch, the AFGC robustly converges to within 728 μV of the desired input offset (mean offset −109 μV, standard deviation 379 μV). Adaptation occurs within milliseconds, with charge retention for more than one month, and variation of offset error with temperature of −15 μV/^∘C.Yanyi Liu Wong received the B.S. and M.S. degrees in Electrical Engineering in 2001 and 2004, respectively, from the University of Maryland, College Park, where he is currently working toward the Ph.D. degree. From 2001 to 2003, he was a Teaching Assistant for microelectronics lectures and labs. Since 2003, he has been with The Johns Hopkins University Applied Physics Laboratory developing Radiation-Hardened-By-Design EEPROM subsystems for space based ASICs. At the same time, he has been working as a Research Assistant at the Integrated Biomorphic Information Systems Laboratory, UMCP, and has been actively designing low-power, mixed-signal, adaptive floating gate circuits and applications in commercially available CMOS processes.Marc H. Cohen received both B.Sc. and M.Sc. degrees in Electrical Engineering from the University of the Witwatersrand, Johannesburg, South Africa in 1978 and 1983 respectively. He received an M.S. in Biomedical Engineering and a Ph.D. in Electrical and Computer Engineering from The Johns Hopkins University, Baltimore, MD, USA in 1991 and 2001 respectively. He is currently an Assistant Research Scientist in the Institute for Systems Research, University of Maryland, College Park. His research interests lie in the areas of adaptive low power analog and mixed-signal integrated circuit design. Current application areas include ultrasonic echolocation, contact imagers for control of microfluidic devices, controllers for adaptive optics and integrated sensors for RFID.Pamela A. Abshire received the B.S. degree in physics with honor in 1992 from the California Institute of Technology. Between 1992 and 1995 she worked as a Research Engineer in the Bradycardia Research Department of Medtronic, Inc. She received her M.S. and Ph.D. degrees in Electrical and Computer Engineering from The Johns Hopkins University in 1997 and 2002, respectively. She is currently an assistant professor in the Department of Electrical and Computer Engineering and the Institute for Systems Research at the University of Maryland, College Park. Dr. Abshire’s research focuses on low power mixed signal integrated circuit design, adaptive integrated circuits, integrated circuits for biosensing, and understanding the tradeoffs between performance and energy in natural and engineered systems.     

A Novel Bandpass Filter Based on Current Feedback Amplifier

An application demonstrating some advantages of the current feedback amplifier (CFA) over the voltage op-amp counterpart is given. A novel bandpass filter achieving a high quality factor and variable gain based on a single CFA is proposed. It is shown that unlike the op-amp Sallen-Key bandpass filter, the CFA filter is more suitable for high frequency applications. Hussain A. Alzaher was born in Qatif-Alawamia, Saudi Arabia, in 1972. He received the B.S. and M.S. degrees (with honors) in electrical engineering from King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia, in 1994 and 1997, respectively, and the Ph.D. degree from The Ohio State University, Columbus, in 2001. Since 1994, he has been with KFUPM as a faculty member in the electrical engineering department. His research interest includes applications of electronic circuit techniques for wireless communications: Multi-standard mobile phones, Bluetooth, WLAN and WiMAX. Dr. Alzaher is the recipient of the 1994/1995 Prince Muhammed bin Fahd bin Abdulaziz Award for Excellence in Scientific Achievement. He is also the recipient of the 2003 Showman award for Young Arab Researchers, Engineering Science.     

A CMOS Low-Dropout Regulator With Current-Mode Feedback Buffer Amplifier

Current feedback amplifiers (CFAs) provide fast response and high slew rate with Class-AB operation. Fast response, low-dropout regulators (LDRs) are critical for supply regulation of deep-submicron analog baseband and RF system-on-chip designs. An LDR with an CFA-based second stage driving the regulation field-effect transistor is presented. The low dropout (LDO) achieves an output noise spectral density of 67.7 nV radicHz, and PSR of 38 dB, both at 100 kHz. In comparison to an equivalent power consumption voltage feedback buffer LDO, the proposed CFA-based LDO settles 60% faster, achieving 0.6- settling time for a 25-mA load step. The LDO with CFA buffer is designed and fabricated on a 0.25- CMOS process with five layers of metal, occupying 0.23- silicon area.     

一种动态开关电容运算放大器共模负反馈电路

本文主要介绍了一种应用于Cascode结构运放中的开关电容共模负反馈电路，它具有稳定性好、对运放频率特性影响小、不消耗额外功率等优点。对电路运用Hspice进行了模拟，并给出了模拟结果。     

A Monolithic GaAs DC to 2-GHz Feedback Amplifier

Resistive feedback in low-frequency FET amplifiers is an attractive method of simultaneously attaining gain flatness and excellent input-output VSWR over wide bandwidths. Combined with simple matching circnitry, the feedback approach allows the design of general-purpose utility amplifiers requiring much less chip area than when conventional matching techniques are used, The 1.5- by 1.5-mm chip desenbed in this paper provides 10-dB +-1-dB gain, excellent input and output VSWR, and saturated output power in excess of +20 dBm, from below 5 MHz to 2 GHz. The noise figure is approximately 2 dB when biased for minimum noise, with an associated gain of 9 dB.     

纳米双栅MOSFET栅极漏电流的二维量子模拟(英文)

基于非平衡格林函数(NEGF)的量子输运理论框架,对双栅MOSFET进行了二维实空间数值模拟。在对表征载流子电势的泊松方程自洽求解后,感兴趣的物理量(如亚阈值摆幅、漏致势垒下降、载流子密度、电流密度等)可以被求得,观察了由栅极注入效应导致的二维电荷分布,并对不同电介质材料对栅极漏电流的影响进行了研究。此外,还通过调整电介质参数并进行比较的方法,研究了电介质的有效质量、介电常数、导带偏移对栅极漏电流的影响。该模拟方法为双栅MOSFET中载流子自栅极的注入提供了良好的物理图景,对器件特性的分析和比较有助于栅氧层高k电介质材料的选取。     

放大电路中反馈类型的判断

反馈在电子技术中得到了广泛的应用,在放大电路中经常引入负反馈来改善电路的工作状态和性质。该文主要分析了反馈的几种类型及反馈类型的判别方法,通过一些简捷的判别方法可以快速判断一个放大电路是什么类型的反馈,以便对电路的性能有更好的了解。     

一种BiCMOS工艺的AB类自适应偏置输出级

介绍了一种采用 Bi CMOS工艺技术制造的具有较大的驱动能力、转换速率和较低的功耗的 AB类输出级。他是利用跨导线性原理实现自适应偏置的 AB类输出级。通过对这种结构的工作原理 ,结构特点的分析 ,仿真得出电阻负载为 2 kΩ ,电容负载为 1 0 0 p F时的最大上升、下降转换速率分别为 4 0 V/μs和 30 V/μs;在± 1 5 V的电源下 ,静态功耗小于 1 0 m W。     

Automatic Gate Biasing of an SCCMOS Power Switch Achieving Maximum Leakage Reduction and Lowering Leakage Current Variability

Power switch transistors are very effective in cutting the leakage currents of digital circuits in a deep-freeze mode, by de-supplying unused blocks. Among existing power switch transistors, Super Cut-off CMOS (SCCMOS) is the most suited to a low supply voltage environment since it uses a low threshold voltage transistor. This power switch type achieves good leakage reduction results, provided that an optimal voltage is applied on its gate in order to maximize the leakage gain. This optimal voltage value, depending on the operating conditions (process, voltage, temperature), cannot be determined at the design level. A polarization circuit, that automatically finds the optimal bias voltage whatever the environment conditions, was therefore designed and fabricated. This circuit, made in Bulk 65 nm technology, achieves more than two decades leakage current reduction at the power switch level, for a power dissipation overhead of 45 nW at ambient temperature. A very simple scheme is also presented to alleviate the voltage stress applied on the dielectric in case of an ageing of the latter, increasing its time-to-breakdown by several orders of magnitude.     

射频功率放大器的自适应前馈电路设计

先分析常用双环自适应前馈电路降低非线性失真及输出功率的特点和不足,通过引入另一个前馈电路,从主功率放大器的输入端耦合部分信号到辅助功率放大器的输入和输出端,经适当调节,进一步改善电路的三阶交调失真(IMD3),并增大输出功率.结果显示,这种改进的自适应前馈电路,IMD3低于信号功率-75dBc,线性度改善效果明显,而且输出功率增大了2～3dB.     

一种带功率检测和自适应偏置的CDMA功率放大器

设计了一款包含功率检测和自适应线性化偏置电路的CDMA功率放大器,功率检测器能根据输入信号的大小来调整功率管的偏置点,大幅提升低功率输出时的效率,从而提升系统整体效率;自适应线性化偏置能有效抑制功率放大器的增益压缩和相位失真,改善其线性度.采用2 μm InGaP/GaAs HBT晶体管工艺成功流片,测试结果表明,与普...     

Miller Theorem for Weakly Nonlinear Feedback Circuits and Application to CE Amplifier

The paper presents the derivation of Miller formulas for weakly nonlinear feedback networks. The expressions found are simple and compact and constitute a generalization of the well-known linear case.      

Low‐Voltage CMOS Current Feedback Operational Amplifier and Its Application

A novel low‐voltage CMOS current feedback operational amplifier (CFOA) is presented. This realization nearly allows rail‐to‐rail input/output operations. Also, it provides high driving current capabilities. The CFOA operates at supply voltages of ±0.75 V with a total standby current of 304 µA. The circuit exhibits a bandwidth better than 120 MHz and a current drive capability of ±1 mA. An application of the CFOA to realize a new all‐pass filter is given. PSpice simulation results using 0.25 µm CMOS technology parameters for the proposed CFOA and its application are given.     

FC-ABS调度算法及在NCS中的应用

针对网络控制系统(Network Control Systems, NCS)节点中的非周期任务,设计了一种FC-ABS调度算法.该调度算法可以根据非周期任务的时间特性采取不同的调度方式,并通过反馈调度减小非周期任务调度对周期任务的影响.仿真实验证明了算法的正确性.     

NURBS在自适应hp有限元分析系统中的应用

在传统的有限元分析中,对于曲边区域或者曲边的分界面并没有很好的近似方法,通常使用大量的线性单元近似的描述曲边计算区域.这些新增加的单元不仅浪费了计算时间,而且往往并不是需要求解的部分.采用曲线单元可以避免对单元的强制细化,有效的提高计算的精度.曲边单元使用非均匀有理B样条（NURBS）曲线实现,可以有效的消除几何离散误差,保证整体的高阶连续性.详细讨论了基于NURBS曲线的自适应三角形网格剖分和四边形网格剖分,并结合自适应hp有限元算法解决实际问题.从计算自由度和计算时间的角度比较典型的工程算例结果,采用NURBS曲边单元的hp有限元算法能够很好的消除几何近似导致的误差,提高计算的效率.     

一种具有自适应关联门的杂波中机动目标跟踪算法

针对杂波环境下的机动目标跟踪,该文提出一种基于自适应关联门的跟踪算法。该算法以传统交互多模型概率数据关联算法为基础,在关联门内无有效量测点迹时,假设目标在前一滤波时刻或是更早时刻以最大机动水平改变原运动模式,利用该假设条件下所获得的目标预测量测及当前真实预测量测,对用于确定关联门的新息协方差进行修正,使得关联门逐步适当扩大,以尽可能地包含目标真实量测点迹。仿真结果表明,自适应关联门跟踪算法能在不影响跟踪精度和算法运算量的情况下,有效降低机动目标的跟踪丢失概率。