电容器贮存电荷能力与可靠性

试图探讨铝电解电容器贮存电荷的能力与电容器可靠性之间的关系。用自放电电压的高低来判定电容器的质量。用铝电解电容器常规的三参数(电容量、漏电流、损耗角正切值)检验电容器的可靠性有一定的局限性,而电容器贮存电荷的能力却与电容器的可靠性之间更有直接的关系,实验证明:在其他条件一定的情况下,电容器自放电电压越高,电容器的可靠性越高。     

一种用于PCRAM的嵌入式片内电容电荷泵

针对相变存储器小片内电容和低功耗的应用要求,在分析传统升压式电容电荷泵局限性的基础上,提出了一种应用于相变存储单元的嵌入式片内电容电荷泵。该电容电荷泵无需电感器件,存储单元不会受到高电磁干扰,采用了特殊的互补型电荷泵升压方法,具有电源效率高、瞬态响应速度快、面积小、电容可片内集成等优点。在SMIC 40 nm标准CMOS工艺条件下,对设计的嵌入式片内电容电荷泵进行仿真。结果表明,负载电流变化为250 mA/μs时,输出瞬态响应时间为374.2 ns,电源转换效率可达81.65%,静态电流为7.22 μA,输出能力为4 V/2.5 mA。     

储能放电用高压大容量铝电解电容器

对储能大电流放电用高压大容量铝电解电容器，要求其漏电流小、等效串联电阻值小、电容量稳定性好、一致性好等。为确保这些特性要求，可通过稳定介质膜性能，研制相应的工作电解液，优配电极片，降低引出条和极片之间的接触电阻等工艺措施达到。对电容器的组合应用，要注意均衡性     

Novel Ceramic Composite Substrates for High-Density and High Reliability Packaging

This paper presents the development and evaluation of a large-area carbon-silicon carbide (C-SiC) based composite board material that has the advantages of organic boards in terms of large-area processability and machinability at potentially low-cost while retaining the high stiffness (> 200 GPa) and Si-matched coefficient of thermal expansion (CTE) (~ 2.5 ppm/degC) of ceramics. Test vehicles were fabricated using C-SiC boards for assessing ultra-fine pitch solder joint reliability without underfill as well as the reliability of high-density wiring with microvias on the board. Finite element reliability models were developed to simulate the thermomechanical behavior of test vehicles. From the finite-element simulations as well as accelerated reliability tests, the high stiffness low-CTE C-SiC boards did not show any premature solder joint fatigue failure or dielectric cracking. Furthermore, the C-SiC boards show minimal via-pad misalignment and support the multilayer buildup structure required to achieve very high wiring density. The modeling and experimental results suggest that the low-cost large-area ceramic matrix composite (C-SiC) has superior thermomechanical properties, and is, therefore, a promising candidate substrate material for the emerging microelectronic systems.     

磁电复合薄膜用高性能压电陶瓷靶材的制备

采用固相法制备了高性能的Pb(Zr0.54Ti0.46)O3压电陶瓷靶材。通过调整Sr掺杂比例,获得高性能的压电陶瓷配方,以高性能锆钛酸铅(PZT)粉体为原料,经冷等静压和高温烧结制备出磁控溅射需要的、直径为73.6mm的压电陶瓷靶材。     

神光Ⅲ强激光能源模块高储能密度电容器的快速保护

分析了大功率激光脉冲电源高储能密度电容器快速保护的必要性 ,提出了电感和特种熔断器快速保护技术路线 ,介绍了快速保护熔断器设计方法。试验表明 ,所研制的熔断器故障情况下可在四分之一周期时间内快速动作 ,使电容器反向电压不超过 10 %,已成功应用于神光Ⅲ能源模块高储能密度电容器的保护。     

Understanding the Charge Storage Mechanism to Achieve High Capacity and Fast Ion Storage in Sodium‐Ion Capacitor Anodes by Using Electrospun Nitrogen‐Doped Carbon Fibers

Microporous nitrogen‐rich carbon fibers (HAT‐CNFs) are produced by electrospinning a mixture of hexaazatriphenylene‐hexacarbonitrile (HAT‐CN) and polyvinylpyrrolidone and subsequent thermal condensation. Bonding motives, electronic structure, content of nitrogen heteroatoms, porosity, and degree of carbon stacking can be controlled by the condensation temperature due to the use of the HAT‐CN with predefined nitrogen binding motives. The HAT‐CNFs show remarkable reversible capacities (395 mAh g^?1 at 0.1 A g^?1) and rate capabilities (106 mAh g^?1 at 10 A g^?1) as an anode material for sodium storage, resulting from the abundant heteroatoms, enhanced electrical conductivity, and rapid charge carrier transport in the nanoporous structure of the 1D fibers. HAT‐CNFs also serve as a series of model compounds for the investigation of the contribution of sodium storage by intercalation and reversible binding on nitrogen sites at different rates. There is an increasing contribution of intercalation to the charge storage with increasing condensation temperature which becomes less active at high rates. A hybrid sodium‐ion capacitor full cell combining HAT‐CNF as the anode and salt‐templated porous carbon as the cathode provides remarkable performance in the voltage range of 0.5–4.0 V (95 Wh kg^?1 at 0.19 kW kg^?1 and 18 Wh kg^?1 at 13 kW kg^?1).     

Exploring the Energy Storage Mechanism of High Performance MnO2 Electrochemical Capacitor Electrodes: An In Situ Atomic Force Microscopy Study in Aqueous Electrolyte

The basic microstructure‐dependent charge storage mechanisms of nanostructured MnO₂ are investigated via dynamic observation of the growth and in situ probing the mechanical properties by using in situ AFM in conjunction with in situ nanoindentation. The progressive nucleation followed by three‐dimensional growth yields pulsed current deposited porous nanostructured γ‐MnO₂, which exhibits a high specific capacitance of 437 F/g and a remarkable cycling performance with >96% capacitance retention after 10 000 cycles. The proton intercalation induced expansion of MnO₂ can be self‐accommodated by the localized compression and reduction of the porosity. More coincidentally, the proton intercalation induced softening is favorable for the elastic deformation of MnO₂. This self‐adaptive capability of nanostructured MnO₂ could generate high structural reliability during cycling. These discoveries offer important mechanistic insights for the design of advanced electrochemical capacitors.     

An Alternative Setup for a Base-Station Cellular Antenna

This paper proposes the use of an alternative setup of a cellular base-station antenna with the potential of reducing the cochannel interference. The setup uses a different cell antenna placement strategy where there is one base-station antenna per cell located high at its center. Unlike a traditional base-station antenna radiating in the horizontal direction, the antenna under consideration radiates downward. The beamwidth of the antenna is considered to be wide enough to match the cell diameter. In addition, the radiation pattern beyond the associated beamwidth is assumed to possess a large attenuation. This paper studies the use of the proposed antenna setup by examining the cell geometry and grouping and its effect on the antenna radiation pattern. It is shown that for a sufficiently large attenuation pattern beyond the antenna beamwidth, the corresponding signal-to-interference ratio can be made significantly larger than the one resulting from the traditional antenna setup     

一种用于LCD驱动的高效电荷泵的设计

电荷泵是一种流行的获取高于供电电源的直流电压转换技术.传统的电荷泵电路采用二极管连接的NMOS管级联来获取较高的电压,由于阈值电压的作用,这种电荷泵的提升效率会随着级数的增加而下降.为了提高效率,文中提出了一种提升5倍电压的采用液晶显示器(LCD)驱动的新型电荷泵结构.特别设计了开关管的栅控电路,消除了阈值电压对电压提升效率的影响,并且通过对开关管尺寸和控制时钟的进一步优化,提高了电压转换效率,降低了功耗,特别适合于小尺寸LCD驱动的需要.     

An Exploration of New Energy Storage System: High Energy Density,High Safety,and Fast Charging Lithium Ion Battery

Rechargeable lithium ion battery (LIB) has dominated the energy market from portable electronics to electric vehicles, but the fast‐charging remains challenging. The safety concerns of lithium deposition on graphite anode or the decreased energy density using Li₄Ti₅O₁₂ (LTO) anode are incapable to satisfy applications. Herein, the sulfurized polyacrylonitrile (SPAN) is explored for the first time as a high capacity and safer anode in LIBs, in which the high voltage cathode of LiNi_1/3Co_1/3Mn_1/3O₂ (NCM‐H) is further introduced to configure a new SPAN|NCM‐H battery with great fast‐charging features. The LIB demonstrates a good stability with a high capacity retention of 89.7% after 100 cycles at a high voltage of 3.5 V (i.e., 4.6 V vs Li⁺/Li). Particularly, the excellent rate capability is confirmed and 78.7% of initial capacity can still be delivered at 4.0C. In addition, 97.6% of the battery capacity can be charged within 2.0C, which is much higher than 80% in current fast‐charging application standards. The feature of lithiation potential (>1.0 V vs Li⁺/Li) of SPAN avoids the lithium deposition and improves the safety, while the high capacity over 640 mAh g^?1 promises 43.5% higher energy density than that of LTO‐based battery, enabling its great competitiveness to conventional LIBs.     

Electrically Programmable Bistable Capacitor for High‐Frequency Applications Based on Charge Storage at the (Ba,Sr)TiO3/Al2O3 Interface

Hysteresis is induced in paraelectric (Ba,Sr)TiO₃ (BST) thin‐film capacitors by inserting an Al₂O₃ barrier layer of a few nanometers in thickness between the BST layer and the electrode. The observed hysteresis is explained by ambipolar charge carrier injection through the Al₂O₃ layer and charge storage at the BST/Al₂O₃ interface. The magnitude of the hysteresis can be directly adjusted by manipulating the thickness ratio between BST and Al₂O₃. Taking into account the low loss of (Ba,Sr)TiO₃ capacitors, the observed switching and retention characteristics are suitable for application as non‐volatile programmable high‐frequency devices, e.g., in radio‐frequency identification.     

用于电机驱动芯片的高压电荷泵电路设计

基于开关电容系统理论,提出了一种用于步进电机芯片中H桥驱动电路的电荷泵电路。电路设计了零温度系数的高压压差检测电路、线形调制的反馈控制电路和泵电容充电电流控制电路。基于HHNEC 0.35μm BCD工艺平台进行电路设计,并完成流片。测试结果显示,电荷泵电路输出电压跟随输入电压线性变化,输出电压范围为13 V~41 V,纹波电压大小约为560 mV。所获结果与设计目标保持一致,证明了设计思想的正确性。     

Electrowetting-Assisted Generation of Ultrastable High Charge Densities in Composite Silicon Oxide–Fluoropolymer Electret Samples for Electric Nanogenerators

Electric nanogenerators that directly convert the energy of moving drops into electrical signals require hydrophobic substrates with a high density of static electric charge that is stable in “harsh environments” created by continued exposure to potentially saline water. The recently proposed charge-trapping electric generators (CTEGs) that rely on stacked inorganic oxide–fluoropolymer (FP) composite electrets charged by homogeneous electrowetting-assisted charge injection (h-EWCI) seem to solve both problems, yet the reasons for this success have remained elusive. Here, systematic measurements at variable oxide and FP thickness, charging voltage, and charging time and thermal annealing up to 230 °C are reported, leading to a consistent model of the charging process. It is found to be controlled by an energy barrier at the water-FP interface, followed by trapping at the FP-oxide interface. Protection by the FP layer prevents charge densities up to −1.7 mC m⁻² from degrading and the dielectric strength of SiO₂ enables charge decay times up to 48 h at 230 °C, suggesting lifetimes against thermally activated discharging of thousands of years at room temperature. Combining high dielectric strength oxides and weaker FP top coatings with electrically controlled charging provides a new paradigm for developing ultrastable electrets for applications in energy harvesting and beyond.     

用于分数频率综合器的改进型电荷平均电荷泵

介绍了一种改进型的电荷平均电荷泵以及相应的电路实现.文章在对Yido Koo首先提出的电荷平均电荷泵结构分析的基础上提出了改进型的实现方式.相比于原结构,这种新型电路能够节省1/3的功耗并且消除了原先结构在实际实现中的一些问题.Spec-tre Verilog行为级仿真结果证明该结构能够有效降低杂散能量.本文同时设计了一个针对分数分频比为1/3的小数频率综合器的改进型电荷共享电荷泵,并通过多层次仿真的方式来验证其可行性.从仿真结果可以看出,这种新结构输出电压稳定,从而能够有效消除频率综合器中的分数杂散.     

用于分数频率综合器的改进型电荷平均电荷泵

介绍了一种改进型的电荷平均电荷泵以及相应的电路实现.文章在对Yido Koo首先提出的电荷平均电荷泵结构分析的基础上提出了改进型的实现方式.相比于原结构,这种新型电路能够节省1/3的功耗并且消除了原先结构在实际实现中的一些问题.Spec-tre Verilog行为级仿真结果证明该结构能够有效降低杂散能量.本文同时设计了一个针对分数分频比为1/3的小数频率综合器的改进型电荷共享电荷泵,并通过多层次仿真的方式来验证其可行性.从仿真结果可以看出,这种新结构输出电压稳定,从而能够有效消除频率综合器中的分数杂散.     

An Optimal Control Method for Buck ConvertersUsing a Practical Capacitor ChargeBalance Technique

A novel control method is presented in this paper which utilizes the concept of capacitor charge balance to achieve optimal dynamic response for Buck converters undergoing a rapid load change. The proposed charge balance method is implemented with analog components and is cheaper and more effective than its digital counterparts since complex arithmetic and sampling delay is eliminated. The proposed controller will consistently cause the Buck converter to recover from an arbitrary load transient with the smallest possible voltage deviation in the shortest possible settling time. Since the controller is nonlinear during transient conditions, it is not limited by bandwidth/switching frequency. Unlike conventional linear controllers, the dynamic response (voltage deviation, settling time) of the proposed controller can be estimated using a set of equations. This greatly simplifies the design process of the output filter. Simulation and experimental results show the functionality of the controller and demonstrate the superior dynamic response over that of a conventional linear controller.      

高性能集成锁相环中低失配电荷泵的设计

在分析电荷泵结构、工作原理和产生杂散机理的基础上,该文提出了一种低静态电流失配、低时序失配的高性能电荷泵。此电荷泵通过减小电荷泵开关过程中时序失配和电流失配,减小了高频锁相环中的抖动和杂散。基于中芯国际0.18 m CMOS射频工艺技术和1.8 V电源电压,对采用此高性能电荷泵的锁相环进行了相位噪声仿真。仿真结果验证了这些锁相环具有低噪声特性：在480 MHz的输出频率下,二阶锁相环的周期抖动为1.05 ps,最大参考杂散为-121 dBc。     

Magnetic Tape for Data Storage: An Enduring Technology

Magnetic tape as used for data storage is reviewed. Attributes such as bit and track densities, tape cartridge capacities and data rates are discussed in terms of the growth seen over time together with future trends envisioned for tape. Tape has seen almost six orders of magnitude density increase since its introduction as a computer data storage device in the early 1950's with 1 Terabyte native capacity tape cartridges being introduced into the market. The recording methods and technologies used for tape data storage devices are outlined and tapes position in the storage landscape discussed. Most of the world's data is stored and archived on magnetic tape primarily because of its long shelf life and favorable cost factors.