Analog circuit optimization system based on hybrid evolutionary algorithms

This paper investigates a hybrid evolutionary-based design system for automated sizing of analog integrated circuits (ICs). A new algorithm, called competitive co-evolutionary differential evolution (CODE), is proposed to design analog ICs with practical user-defined specifications. On the basis of the combination of HSPICE and MATLAB, the system links circuit performances, evaluated through electrical simulation, to the optimization system in the MATLAB environment, once a circuit topology is selected. The system has been tested by typical and hard-to-design cases, such as complex analog blocks with stringent design requirements. The results show that the design specifications are closely met, even in highly-constrained situations. Comparisons with available methods like genetic algorithms and differential evolution, which use static penalty functions to handle design constraints, have also been carried out, showing that the proposed algorithm offers important advantages in terms of optimization quality and robustness. Moreover, the algorithm is shown to be efficient.     

基于几何规划的模拟器件建模与电路性能优化

基于分段线性函数,提出一种新的对模拟器件进行建模的方法,并提出乐观、悲观两种数据拟合算法,两种算法均能较好地拟合MOS管参数。模型建立之后,利用几何规划对电路性能进行优化。乐观算法会得到较好的电路性能,但可能不满足约束条件;悲观算法能够严格满足约束条件,但是得到的电路性能未必最优。在此基础上,提出一种基于响应曲面方法的折衷优化算法,能够得到综合考虑电路性能和约束条件的电路设计参数。最后,以两级放大器为优化实例,证明该方法的有效性。     

粒子群算法优化特征和神经网络的模拟电路故障诊断

模拟电路受到自身特性和外界环境的影响,故障变化具有非线性、时变性,针对当前模拟电路故障诊断模型的特征和分类器参数不匹配的难题,提出一种粒子群算法选择特征和神经网络的模拟电路故障诊断模型。首先对当前模拟电路故障诊断现状进行分析,指出它们存在的缺陷;然后提取模拟电路故障诊断特征,利用神经网络作为模拟电路故障诊断分类器;最后采用粒子群算法对模拟电路故障特征与神经网络参数进行优化,在Matlab 2012平台进行了仿真实验。结果表明,该模型的模拟电路故障诊断性能要远远优于其他参比模型,具有广泛的应用前景。     

ANALOG CIRCUIT IMPLEMENTATION OF NEURAL NETWORK WITH HIGH PRECISION WEIGHTS

A current-mode MOS neuron circuit with 4-bit programmable weights is presented by using CMOS technology. The weights of the neurcn have high resolution and also can easily be digitally stored. The resolution can be extended into high levels such as 8-bit, etc. by the design methodology presented in this paper. The operational principle of the neuron is discussed. Circuit simulation has been made by use of SPICE II. The results give a good agreement for the design requirements.     

Second-derivative sensitivity using the concept of the adjoint network

Second-derivative sensitivities for linear time-invariant networks are derived by an extension of the method used by Director and Rohrer to calculate first-derivative sensitivities.     

Analog circuit soft-fault diagnosis based on sensitivity analysis with minimum fault number rule

This paper proposes a new single or multiple soft analog circuit fault diagnosis approach based on the minimum fault number rule. It is based on the consideration that the fact that the probability of a single soft fault is much greater than that of a multiple fault if the related fault modes are independent. In this way, a new diagnostic strategy based on the circuit sensitivity analysis is proposed. The proposed strategy is an optimization-based one, whose objective is to find the minimum value of unaccepted parameter deviations which satisfy all those constraints, and the constraints equations are actually the voltage increment equations in all test nodes and the changing range of each element. The diagnosis process can fulfill the requirement of fault detection and fault isolation. It enables a fast or a real-time diagnosis in practical engineering. A DC circuit example and an AC circuit example are presented to demonstrate the effectiveness of the proposed approach.     

Analog circuit design optimization based on symbolic simulation andsimulated annealing

A methodology for the automatic design optimization of analog integrated circuits is presented. A non-fixed-topology approach is realized by combining the optimization program OPTIMAN with the symbolic simulator ISAAC. After selecting a circuit topology, the user invokes ISAAC to model the circuit. ISAAC generates both exact and simplified analytic expressions, describing the circuit's behavior. The model is then passed to the design optimization program OPTIMAN. This program is based on a generalized formulation of the analog design problem. For the selected topology, the independent design variables are automatically extracted and OPTIMAN sizes all elements to satisfy the performance constraints, thereby optimizing a user-defined design objective. The global optimization method used on the analytic circuit models is simulated annealing. Practical examples show that OPTIMAN quickly designs analog circuits, closely meeting the specifications, and that it is a flexible and reliable design and exploration tool     

基于多分辨分析和WNN的模拟电路故障诊断

提出了一种基于多分辨分析和小波神经网络(WNN)相结合的模拟电路故障诊断方法。该方法利用了多分辨分析优异的时频特性,提取采集数据中的故障特征参数值,结合小波神经网络强大的非线性分类、学习、泛化能力及精度高、收敛速度快等特性,将得到的输入数据进行归一化处理作为小波神经网络的输入对其进行训练,并将训练的结果应用于滤波器电路故障诊断。结果表明,该方法实现了对故障模块的定位,是一种有效的模拟电路故障诊断方法。     

基于泛函网络求解随机优化问题的EM算法

研究了一类带有随机变量的不确定优化问题。为了解决这类随机优化问题,首先用随机仿真为泛函网络产生训练样本,用泛函网络逼近随机函数的均值,将随机函数的均值转为不合随机变量的确定性函数,然后用类电磁算法求解确定性函数的最优解。最后,给出一些数值例子验证了所提算法的有效性。     

信令分析在TD-LTE网络优化中的应用分析

目前,随着移动通信公司的发展,TD-LTE网络系统也逐渐出现在了人们的视野中.我们应该充分重视到TD-LTE网络优化工作,应用信令分析发挥TD-LTE的最大效用.因此,本文首先探究了在TD-LTE网络优化中应用到信令分析的作用,重点分析了信令分析在TD-LTE网络优化中的应用以及增强TD-LTE网络优化中的有效应用的措施,以此来提高网络质量与安全,解决网络发展中存在的问题.     

Analog circuits optimization based on evolutionary computation techniques

This paper presents a new design automation tool, based on a modified genetic algorithm kernel, in order to improve efficiency on the analog IC design cycle. The proposed approach combines a robust optimization with corner analysis, machine learning techniques and distributed processing capability able to deal with multi-objective and constrained optimization problems. The resulting optimization tool and the improvement in design productivity is demonstrated for the design of CMOS operational amplifiers.     

基于二叉树的CVSL电路优化方法

CVSL电路不同于互补CMOS逻辑那样具有固定的构成规则,对于复杂逻辑,若不对电路进行优化,则电路速度、版图面积、功耗等性能指标均会受到影响。因此用一种方法有规律的来完成CVSL电路结构的设计显得十分重要,传统的卡诺图化简法步骤过多,结构不够直观,针对这一缺陷,提出了用二叉树代替传统的卡诺图法的设计思路,从而使CVSL电路结构得到优化。分析结果表明,二叉树优化法较卡诺图法可使电路获得了更加高效的设计结果。     

基于量子粒子群优化的SVM的模拟电路故障诊断

相比于小波变换,小波包变换具有较高的分辨率和细致的分析能力,是小波变换的延伸和发展。支持向量机具有较好的泛化能力,能够应用于模拟电路的故障诊断。鉴于支持向量机参数难以确定的问题,采用量子粒子群优化算法选取支持向量机的参数,将优化后的支持向量机与小波包变换相结合,利用小波包变换提取电路的故障特征,然后通过优化后的支持向量机对特征向量进行分类识别。最后通过对实例的分析,验证该方法的有效性。     

基于l2正则化回声状态网络的模拟电路故障诊断

为了提高模拟电路故障诊断的准确率,提出了一种基于l2正则化回声状态网络（l2-RESN）的模拟电路故障诊断方法。l2-RESN在ESN的约束优化函数中引入l2正则化因子,推导带正则化因子的ESN输出权重计算公式,避免传统的ESN算法因矩阵奇异而降低模型泛化能力。实验结果表明,相比于支持向量机（SVM）和标准ESN,l2-RESN的诊断准确率分别提高1.11%和18.34%。证明l2-RESN能够有效提高模拟电路诊断的准确性。     

An analysis method for high-speed circuit systems

A new method for analyzing high-speed circuit systems is presented. The method adds transmission line end currents to the circuit variables of the classical modified nodal approach. Then the matrix equation describing high-speed circuit system can be formulated directly and analyzed conveniently for its normative form. A time-domain analysis method for transmission lines is also introduced. The two methods are combined together to efficiently analyze high-speed circuit systems having general transmission lines. Numerical experiment is presented and the results are compared with that calculated by Hspice.     

A SWITCHED CAPACITOR CIRCUIT ANALYSIS PROGRAM AND ITS APPLICATIONS

A program developed for analyzing arbitrary N-phase switched capacitor circuits is presented.Application of the program is given.The program simulation facilities,such as time-domain analysis,frequence-domain analysis,sensitivity analysis and multiple ohjective optimization are described.Thealgorithm used in the program is introduced briefly.Several examples are given to show the application of theprogram.     

PCBA分板与开短路浅析

PCBA分板包括装配前分板和装配后分板,前者只有在进行回流焊后需要进行小单元局部的选择性波峰焊时才应用得到,而后者较为普遍。根据装配拼板的小单元之间连接设计的不同,PCBA分板可以分为V槽分板、吊点分板、邮票孔分板等方法。PCBA分板过程如若处理不当,一些非PCB缺陷不良的开短路也会随之而生。本文通过分析一些PCBA分板不良所导致的开短路失效范例供借鉴,以及提出优化的分板方式,目的是提高PCBA分板质量和避免不必要的品质纠纷与经济损失。     

Analysis of circuit tolerance based on random set theory

Monte Carlo Analysis has been an accepted method for circuit tolerance analysis, but the heavy computational complexity has always prevented its applications. Based on random set theory, this paper presents a simple and flexible tolerance analysis method to estimate circuit yield. It is the alternative to Monte Carlo analysis, but reduces the number of calculations dramatically.     

基于信令分析的LTE网络CSFB优化策略

针对LTE网络下采用CSFB方式实现语音业务存在时延过大的问题，探索基于信令分析的CSFB优化策略，通过信令流程拆分法、信令追溯分析法等精确定位出CSFB回落失败及时延过长的原因，并给出具体解决方案。实验结果表明该策略能够有效改善回落成功率或降低时延，提升了LTE网络的用户感知     

Selection of Input Stimulus for Fault Diagnosis of Analog Circuits Using ARMA Model

The paper addresses the problem of fault diagnosis of analog circuits based on dictionary approach. The proposed approach first identifies an adequate set of test frequencies to optimize the process of detection and isolation of simulated fault scenarios. The circuit under test (CUT) is then excited by an input stimulus composed of a set of sinusoidal waveforms with the selected test frequencies. The circuit response, at different fault scenarios, is preprocessed by an autoregressive moving average (ARMA) model to yield a set of features formulating the fault dictionary. Collected features are utilized to train and test a back-propagation (BP) neural network (NN) based classifier. Demonstrative results from soft fault simulation of two active circuit examples prove the excellent effectiveness of the proposed algorithm.