低耗能流水线模数转换器的运算放大器设计与仿真

基于0.13,μm工艺,设计一个用于1.2,V低电压电源的10比特83MSPS流水线模数转换器的两级运算放大器.该放大器采用折叠共源共栅为第一级输入级结构,共源为第二级输出结构.详细介绍了运算放大器的设计思路、指标确定方法及调试中遇到的问题和解决方法.模拟结果显示:该运算放大器开环直流增益可达79.25,dB,在负载电容为2,pF时的单位增益频率达到838 MHz,在1.2,V低电压下输出摆幅满足设计要求,高达1 V,满足了10比特低电压高速度高精度模数转换器的要求.     

高速CMOS运算跨导放大器

基于全差分结构介绍一种高速CMOS运算跨导放大器,该放大器由折叠共源共栅输入级和共源增益输出级构成,输出级采用极点-零点补偿技术以获取更大的带宽和足够的相位裕度。电路可用在10位20 MSps全差分流水线A/D转换器的采样/保持级或级间减法/增益级中。经过优化设计后,该放大器在0.6μmCMOS工艺中带宽为290 MHz,开环增益为85 dB,功耗为16.8 mW,满足高速A/D转换器要求的性能指标。     

一种高性能低功耗两级全差分运算放大器设计

分析并设计了一种高速、高增益、低功耗的两级全差分运算放大器.该运算放大器用于高速高精度模数转换器中.运算放大器第一级采用增益自举cascode结构获得较大的直流增益,采用2个新的全差分运算放大器替代传统的4个单端运算放大器作为增益自举结构.该放大器采用SMIC 0.18μm CMOS工艺设计,电源电压1.8 V,直流增益125 dB,单位增益带宽300 MHz(负载3 pF),功耗6.3 mW,输出摆幅峰峰值达2 V.     

一种轨对轨两级CMOS运算放大器的设计

目的 设计一个具有轨对轨输入和输出摆幅的两级CMOS运算放大器.方法 输入级采用两对单一类型的n沟道差分对管作为输入管,用两个相同的n沟道源跟随器来完成输入电平的直流电平转移,实现了轨对轨的输入摆幅;输出级采用前馈甲乙类控制的轨对轨输出级,保证了轨对轨的输出摆幅和较强的驱动能力.结果 用标准的0.6μm CMOS BSIM3v3模型库对该放大器进行了仿真,开环电压增益、单位增益带宽和相位裕度分别达到了113.57dB,11.9MHz和53°,输入级跨导的变化在±5%内.结论 所设计运算放大器其输入和输出摆幅为轨对轨,满足设计所提要求.     

双斜率积分ADC中开关电容积分器的设计

为提高双斜率积分ADC中模拟输入信号转换成数字信号的准确性,设计了一种高性能开关电容积分器以替代传统的RC有源积分器。该开关电容积分器的运算放大器由折叠共源共栅输入级和Class AB输出级组成,开关部分选用CMOS开关,以抑制电荷注入和时钟馈通的影响。在中芯国际0.18μmCMOS工艺下,采用EDA仿真软件对相关模块进行仿真验证,得到运算放大器的直流增益为110.3 dB,单位增益带宽为5.64 MHz,相位裕度达到79°,输出摆幅为0.013 3～3 299 mV,转换速率为7.56 MV/s。结果表明,开关电容积分器完全满足双斜率积分ADC的实际应用。     

一种宽频带大摆幅的三级CMOS功率放大器

设计了一种用于耳机驱动的CMOS功率放大器,该放大器采用0.35μm双层多晶硅工艺实现,驱动32Ω的电阻负载.该设计采用三级放大两级密勒补偿的电路结构,通过提高增益带宽来提高音频放大器的性能.仿真结果表明,该电路的开环直流增益为70dB,相位裕度达到86.6°,单位增益带宽为100MHz.输出级采用推挽式AB类结构,能有效地提高输出电压的摆幅,从而得到电路在低电源电压下的高驱动能力.结果表明,在3.3V电源电压下,电压输出摆幅为2.7V.     

基于0.5μm CMOS工艺的高速运放

设计了高单位增益带宽积、大摆率、宽输出摆幅的运算放大器,该运算放采用了两级全差动结构.设计采用增加1个前馈放大级电路,以此产生1个左半平面零点并与第一个次极点相抵消的频率补偿方案,达到了环路稳定的要求.另外,提出一种新颖的共模反馈(CMFB)方案,使共模抑制比达到62dB,电路采用CSMC公司的0.5μm CMOS数模混合信号工艺设计并经过流片.测试结果表明,在单电源3.3 V电压下,运放的直流增益为65.5 dB,单位增益带宽积达350 MHz以及±2.7 V的输出摆幅.     

一种10bit 50MS/s低功耗流水线模数转换器

设计了一个10 bit精度,50 MS/s采样频率的流水线型模数转换器,通过运算放大器共享和省略采样保持实现低功耗.第1级为单比特输出,它能够在将信号摆幅减半的同时保持信噪比不衰减,减半的摆幅使得运放直流增益和带宽要求以及电容匹配要求降低.由于采用运放共享技术,该设计只使用了4个运放,功耗相比传统结构降低1/3.采用0...     

一种基于电平位移电路的低电压全摆幅CMOS运放

为解决阈值电压对电源电压和输入信号的受限问题,提出一种实用的电平位移电路,为运放的输入级提供良好的电平位移。采用互补金属氧化物半导体(CMOS)0.5μm工艺设计的低电压全摆幅CMOS运算放大器,中间级采用适合低电压工作的低压宽摆幅共源共栅结构,输出级采用传统的Class A类得到轨至轨的输出。采用Hspice软件对所设计的电路进行仿真。研究结果表明:当电源电压降至或者小于NMOS与PMOS的阈值电压之和时,在任何共模输入电压下,该运放都能正常工作,实现输入级的全摆幅和恒跨导;在1.3 V单电源供电情形下直流开环增益达106.5 dB,单位增益带宽为2.3 MHz,功耗178.8μW。电路结构简单紧凑,具有实用的电平位移功能,适合于低电压应用。     

低电压全摆幅恒跨导CMOS运算放大器的设计

给出了一种常用两级低电压CMOS运算放大器的输入级、中间增益级及输出级的原理电路图,并阐述其主要工作特性.输入级采用了NMOS管和PMOS管并联的互补差分输入对结构,使输入共模电压范围达到全摆幅（rail-to-rail）,并采用了成比例的电流镜技术以实现输入级跨导的恒定;中间增益级采用了适合低电压工作的低压宽摆幅共源共栅结构的电流镜负载,提高了输出电阻,进而提高了增益,同时更好的实现了全摆幅特性;输出级采用了高效率的推挽共源极功率放大器,使输出电压摆幅基本上可以达到全摆幅;为了保证运放的稳定性与精确性,其基准电流源采用一个带电流镜负载的差分放大器;为防止运放产生振荡,采用了带调零电阻的密勒补偿技术对运放进行频率补偿.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that