一种低功耗无片外电容LDO的设计

基于SMIC 0.18 μm CMOS工艺,设计了一款输入电压为1.8 V、输出电压为1.6 V的低功耗无片外电容低压差线性稳压器(LDO),其静态电流仅为5 μA。该电路采用一种新型摆率增强电路,通过检测输出电压的变化实现对功率管的瞬态调节。片内采用密勒补偿使主次极点分离,整个系统在负载范围内具有良好的稳定性。仿真结果显示,该LDO在负载电流以99 mA/1 μs跳变时,输出电压下冲为59 mV,上冲为60 mV,响应时间约为1.7 μs。     

基于双环调节的快速瞬态响应无片外电容LDO

基于双环路控制构建推挽结构,增强了功率管栅端的摆率,改善了无片外电容LDO的瞬态响应。此外,结合A类复合放大器特性,降低了功率管栅端阻抗,有利于提升LDO的频率稳定性。该LDO输入电压范围为2.0~3.5 V,输出电压为1.8 V,最大负载电流为100 mA。当负载电流在1 μs内从100 μA跳变到100 mA以及从100 mA跳变到100 μA时,最大下冲电压为128 mV,最大上冲电压为170 mV,建立时间分别为2.5 μs和2.4 μs,电路工作时消耗的静态电流仅为12.6 μA。     

一种基于COT控制的快速瞬态响应Buck变换器

设计了一种基于TSMC 0.18 μm CMOS工艺的快速瞬态响应Buck型变换器。基于电流模COT架构的Buck型变换器,结合电容电流采样电路和负载电流调节器,设计了一种新颖的瞬态增强电路,对负载电流进行补偿,有效地减小了恢复时间,提高了输出电压精度。仿真结果表明,没有瞬态增强电路时,负载电流从0 A跳变到3 A,电流变化率为3 A/10 ns,下跌电压为166.9 mV,恢复时间为5.8 μs；加入瞬态增强电路后,下跌电压变为21 mV,恢复时间变为0.5 μs。没有瞬态增强电路时,负载电流从3 A跳变到0 A,电流变化率为3 A/10 ns,过冲电压为73 mV,恢复时间为3.3 μs；加入瞬态增强电路后,过冲电压变为36 mV,恢复时间变为0.6 μs。     

一种快速瞬态响应的无片外电容型LDO

设计了一种快速瞬态响应的无片外电容型LDO。采用高增益高带宽的超级跨导结构(STC)的误差放大器,利用动态偏置技术与电容耦合技术,极大地增强了摆率。引入额外的快速响应环路,进一步提升了瞬态响应速度。基于0.18 μm CMOS工艺进行设计。结果表明,该LDO的最低供电电压为1 V,漏失电压仅为200 mV,可提供最大100 mA的负载电流,能在最大输出电容为100 pF、最低负载为50 μA的条件下保证电路稳定。负载电流在0.5 μs内由50 μA跳变至100 mA时,LDO输出导致的过冲电压和下冲电压分别为200 mV和306 mV。     

车规级LIN总线中55V摆率增强型LDO

针对传统车载芯片中高压型低压差线性稳压器(LDO)的负载电流小、电源抑制比低、瞬态响应差等问题,提出了一种增强型高压LDO,通过一种新型高压预调制电路,提高了高压LDO的电源抑制比;通过一种新型摆率增强电路,改善了高压LDO的瞬态响应。电路基于BCD-120 V CMOS工艺完成建模,仿真结果显示,电压可调范围为5.5～55 V,输出5 V;负载电流为800 mA;低频电源抑制比为96 dB;1μs内负载电流从1 mA跳变到800 mA时,输出端最大上冲电压为26.6 mV,响应时间为8μs;下冲电压为45.4 mV,响应时间为7μs,满足车规级局域互联网(LIN)总线中高压LDO的性能要求。     

一种快速瞬态响应LDO的设计与实现

设计了一种快速瞬态响应LDO。采用缓冲级结构的增强电路,使功率器件在负载瞬态变化时,栅极能够及时响应,从而避免了较大的电压上冲与下冲。加入缓冲级电路以后,系统的稳定性变差,采用密勒补偿和前馈补偿对其进行频率补偿,增加系统的相位裕度,使系统稳定。采用CSMC 0.5 μm工艺,利用Cadence工具完成了整体电路的设计、前仿真、物理版图设计和后仿真,并进行了流片。测试结果表明,设计的LDO输出电压为2.5 V,负载电流在10 mA和300 mA之间变化时,电压最大变化48 mV,响应时间为12.4 μs。     

一种带瞬态响应增强的无电容型LDO

在传统无电容型LDO的基础上,设计了一种带瞬态增强的无电容型LDO。采用频率补偿方案,有效减小所需的片上补偿电容,节约了芯片面积。采用了过冲/下冲检测电路,用于检测负载瞬间变化时输出电压的变化,通过调节功率管栅极电压,提升了LDO的瞬态响应速度。采用0.13 μm标准CMOS工艺,对设计的瞬态增强无电容型LDO进行仿真验证。结果表明,片上补偿电容为2 pF时,系统静态电流为30 μA,当负载在1 μs内从1 mA变化到50 mA时,输出电压过冲为88 mV,下冲为50 mV,与不带过冲/下冲检测电路的LDO相比,分别提高了56%和54%。     

一种低功耗、高稳定性的无片外电容线性稳压器

本文研究并设计了输出电压3.3V,最大输出电流为150mA的CMOS无片外电容的低压差线性稳压器(Off-chipcapacitor-free Low-dropout Voltage Regulator,LDO).该LDO采用了NMC(Nested Miller Compensation)频率补偿技术保证了系统的稳定性.另外,采用大电容环路和SRE(Slew Rate Enhancement)电路抑制输出电压的跳变,改善了瞬态响应.电路采用了低功耗设计技术.采用CSMC 0.5μm CMOS混合信号工艺模型仿真表明:整个LDO的静态电流仅为3.8μA;最差情况下的相位裕度约为88.50;在5V工作电压下,当负载电流在1μs内从150mA下降到1mA时,输出电压变化仅为140mV;在负载电流150mA的情况下,当电源电压在5μs内从3.5V跳变至5V时,输出电压变化也仅为140mV.     

一种低压快速瞬态响应的片上LDO

提出了一种低输入电压的快速瞬态响应片上低压差线性稳压器(LDO)。采用基于反相器的轨-轨输入运放作为误差放大器(EA)的输入级。EA后级采用大抽灌电流能力的STCB结构。LDO加入了高通耦合结构,实现了低输入电压和全负载范围下的快速瞬态响应。该LDO无需外加偏置网络就能实现自启动。在Dongbu 0.5 μm CMOS工艺下,LDO的输入电压为2.2~2.7 V,输出电压为2 V。仿真结果表明,在负载电容为100 pF、压差为200 mV的条件下,该LDO可稳定输出0.1~100 mA的负载电流,负载在0.5 μs范围内切换时的电压尖峰在310 mV以内。     

适用于高频开关芯片的快速瞬态响应LDO设计

设计了一种片外大电容快速瞬态响应低压差线性稳压器。该LDO电路基于跨导线性结构设计,在输出级引入推挽结构,有效地减小过冲的幅值和恢复时间,提高了LDO的瞬态响应速度;利用浮动缓冲器驱动功率管,有效地提高了LDO的电流效率;采用动态零点补偿技术,保证了LDO在全负载范围内的环路稳定性。该LDO电路基于0.35μm BCD工艺设计与仿真验证。结果表明,在1.2 V~3 V输入电压范围,LDO的输出电压为1 V,静态电流约为50μA,可提供0~300 mA的负载。在上升下降沿为500 ns、幅度为300 mA、轻载持续时间为50μs的负载瞬态跳变下,过冲和下冲均小于20 mV。电路满足高频负载跳变的应用需求。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

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.     

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.     

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.     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.