电流模式的高阶曲率补偿CMOS带隙基准源

因为传统的带隙电压基准源只经过了一阶温度补偿,且输出电压只能在1.2 V左右,所以为了得到一个可调的、更高精度的电压基准源,提出了电流模式的带隙电压基准源电路。电路采用了高阶曲率补偿方法,且输出的基准电压可根据输出电阻的大小进行调节。电路采用gpdk090 CMOS工艺,通过Spectre仿真,当电源电压为3.6 V、在-60℃~-120℃温度范围内、温度系数为14.4×10-6/℃时电源电压抑制比为78.3 d B,输出电压平均为1.162 V。     

一种CMOS带隙基准源的设计与仿真

分析了传统带隙基准源的基本原理,并在此基础上一款CMOS带隙基准源电路。该电路基于UMC0.18μm CMOS工艺设计,利用cadence软件进行仿真。仿真结果表明,CMOS带隙基准源稳定输出电压1.22V,该电路在温度从-50-100℃进行扫描,其变化率为10.7ppm/℃,电源电压在1.7V-1.9V范围内发生变化时帯隙基准源输出电压变化很小。     

高精度、低功耗带隙基准源及其电流源设计

提出一种适用于红外焦平面阵列传感器的高精度BiCMOS电压基准和电流基准设计方案。该方案采用新型电压基准输出级降低Brokaw带隙基准源中的厄尔利效应使电流镜电流完全匹配,同时减小电压基准的输出阻抗;接着利用共源共栅结构的偏置电流提高带隙基准的电源抑制PSR(Power Supply Rejection)特性;最后通过4个MOSFET管将基准电压和电阻电压钳制相等,进而得到一个高精度、低温度系数的电流基准;而以单个二极管连接的MOSFET作为电流基准启动电路的方式,可更进一步降低电路复杂性。系统采用CSMC 0.5μm BiCMOS工艺,利用Cadence Spectre工具对电路进行仿真。结果表明,在电源电压5 V,-40℃到125℃温度范围内,基准电压和基准电流的温度系数分别为13×10-6/℃和31×10-6/℃,输出电流波动低于0.5%,整体电路的PSR为-86.83 dB,解决了恒定跨导基准源精度低的缺陷,符合红外焦平面阵列对基准源高精度、高PSR和低功耗的要求。     

一种低功耗差动CMOS带隙基准源

设计了一种采用0.6μmCMOS工艺的低功耗差动带隙基准电压源电路.在设计中采用两个pn结串联结构来减小运放失调电压的影响,并采用自偏置共源共栅运放来改善MOS器件对电源的依赖性.这种带隙基准源输出电压为2V,功耗为2.3mW,温度系数可达到13ppm/℃,主要适用于高精度模拟系统,并带有提高电源抑制比电路和启动电路.     

一种高电源抑制比带隙基准电压源设计

针对实际电路中的电源噪声对带隙基准精度的影响问题,设计一款具有高电源抑制比的带隙基准源。设计包含专用的电源抑制比提高电路,辅以启动电路、带隙主体电路、温度补偿电路等。利用电压负反馈技术,使带隙基准输出电压获得高电源抑制比,减少电源对输出基准电压的干扰。对带隙基准电路设计温度补偿,显著减小温度漂移,可稳定输出2.5 V基准电压。电路在Candance Spectre环境下进行温度特性和电源抑制比的仿真,实验结果表明带隙具有较的低温度系数和较高的电源抑制能力,适用于A/D转换器,DC-DC转换器等高精度电路应用场合。     

高精度低温度系数带隙基准电压源的设计

基于0.5μm双层多晶双层铝CMOS工艺,采用共源共栅电流镜结构和基极电流补偿方法,设计了一种新颖的高性能带隙电压基准.结果表明,在温度-25℃～125℃范围,基准电压温度系数为15.3×10-6V/℃,低频时,电源抑制比可达-80db.该电路可做为A/D和D/A转换器中的基准电压源.     

一种新颖的低电压CMOS带隙基准源设计

设计一种新颖的低电压CMOS带隙基准电压源电路.电路采用了适合低电源电压工作的nMOS输入对管折叠共源共栅运算放大器,并提出一种新颖的启动电路.基于SMICO.35μm标准CMOS工艺,Cadence Spectre仿真结果表明:在低于1-V的电源电压下,所设计的电路能稳定工作,输出稳定的基准电压为622mV,最低电源电压为760mV.不高于100KHz的频率范围内,电源噪声抑制比为-75dB.在-20℃到100℃范围内,温度系数20ppm/℃.     

一种二阶曲率补偿带隙基准的设计

针对高压电源芯片的需要,提出了一种二次曲率补偿的带隙基准源.该电路在传统带隙基准结构的基础上,利用Bipolar管的电流增益随温度呈指数变化的规律,对带隙基准进行高阶温度补偿.该电路具有温度补偿精度高、电路结构简单且能输出高电位电压基准等优点.采用40VBiCMOS高压工艺流片,仿真用Cadence软件中的spectre工具,流片后测试结果为,工作电源电压±12V,输出电压为-10.78V,在-55℃～125℃范围内,温度漂移系数为2.5ppm/℃,在20kHz时基准源输出电源抑制比为100dB.     

一种二阶温度补偿的CMOS带隙基准电路

提出了一种可用于标准CMOS工艺下且具有二阶温度补偿电路的带隙基准源。所采用的PTAT2电流电路是利用了饱和区MOSFET的电流特性产生的,具有完全可以与标准CMOS工艺兼容的优点。针对在该工艺和电源电压下传统的启动电路难以启动的问题,引入了一个电阻,使其可以正常启动。基准核心电路中的共源共栅结构和串联BJT管有效地提高了电源抑制比,降低了温度系数。基于TSMC 0.35μm CMOS工艺运用HSPICE软件进行了仿真验证。仿真结果表明,在3.3V供电电压下,输出基准电压为1.2254V,温度系数为2.91×10-6V/℃,低频的电源抑制比高达96dB,启动时间为7μs。     

一种发动机高温差环境下的基准电压源电路

根据汽车发动机控制芯片的工作环境,针对常见的温度失效问题,提出了一种应用在发动机控制芯片中的带隙基准电压源电路。该电路采用0．181．LmCMOS工艺,采用电流型带隙基准电压源结构,具有适应低电源电压、电源抑制比高的特点。同时还提出一种使用不同温度系数的电阻进行高阶补偿的方法,实现了较宽温度范围内的低温度系数。仿真结果表明,该带隙基准电路在一50℃～＋125℃的温度范围内,实现平均输出电压误差仅5．2ppm／℃,可用于要求极端严格的发动机温度环境。该电路电源共模抑制比最大为99dB,可以有效缓解由发动机在

Abstract：

The paper presents a bandgap reference power source, which is designed to accommodate the wide range temperature environment for engine control modules and to avoid circuit invalidation caused by temperature. The bandgap reference based on current summing     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.