All-optical switch and transistor based on coherent light-controlled single two-level atom coupling with two nanowires

Atom–nanowire coupling system is a promising platform for optical quantum information processing. Unlike the previous designing of optical switch and transistor requiring a dedicated multi-level emitter and high fineness microcavity,a new proposal is put forward which contains a single two-level atom asymmetrically coupled with two nanowires. Singleemitter manipulation of photonic signals for bilateral coherent incident is clear now, since we specify atomic saturation nonlinearity into three contributions which brings us a new approach to realizing light-controlled-light at weak light and single-atom levels. An efficient optically controllable switch based on self-matching-induced-block and a concise optical transistor are proposed. Our findings show potential applications in full-optical devices.

A Silicon Cluster Based Single Electron Transistor with Potential Room-Temperature Switching

We demonstrate the fabrication of a single electron transistor device based on a single ultra-small silicon quantum dot connected to a gold break junction with a nanometer scale separation. The gold break junction is created through a controllable electromigration process and the individual silicon quantum dot in the junction is deter- mined to be a Si 170 cluster. Differential conductance as a function of the bias and gate voltage clearly shows the Coulomb diamond which confirms that the transport is dominated by a single silicon quantum dot. It is found that the charging energy can be as large as 300meV, which is a result of the large capacitance of a small silicon quantum dot （-1.8 nm）. This large Coulomb interaction can potentially enable a single electron transistor to work at room temperature. The level spacing of the excited state can be as large as 10meV, which enables us to manipulate individual spin via an external magnetic field. The resulting Zeeman splitting is measured and the g factor of 2.3 is obtained, suggesting relatively weak electron-electron interaction in the silicon quantum dot which is beneficial for spin coherence time.

Improvement of switching characteristics by substrate bias in AlGaN/AlN/GaN heterostructure field effect transistors

A simple and effective approach to improve the switching characteristics of AlGaN/AlN/GaN heterostructure field effect transistors （HFETs） by applying a voltage bias on the substrate is presented. With the increase of the substrate bias, the OFF-state drain current is much reduced and the ON-state current keeps constant. Both the ON/OFF current ratio and the subthreshold swing are demonstrated to be greatly improved. With the thinned substrate, the improvement of the switching characteristics with the substrate bias is found to be even greater. The above improvements of the switching characteristics are attributed to the interaction between the substrate bias induced electrical field and the bulk traps in the GaN buffer layer, which reduces the conductivity of the GaN buffer layer.

Small-signal modeling of GaN HEMT switch with a new intrinsic elements extraction method

A novel and accurate method is proposed to extract the intrinsic elements of the GaN high-electron-mobility transistor（HEMT） switch.The new extraction method is verified by comparing the simulated S-parameters with the measured data over the 5-40 GHz frequency range.The percentage errors E（ij） within 3.83% show the great agreement between the simulated S-parameters and the measured data.

A low noise charge sensitive preamplifier with switch control feedback resistance

In this paper, the design and analysis of a new low noise charge sensitive preamplifier for silicon strip, Si(Li), CdZnTe and CsI detectors etc. with switch control feedback resistance were described, the entire system to be built using the CMOS transistors. The circuit configuration of the CSP proposed in this paper can be adopted to develop CMOS-based Application Specific Integrated Circuit further for Front End Electronics of read-out system of nuclear physics, particle physics and astrophysics research, etc. This work is an implemented design that we succeed after a simulation to obtain a rise time less than 3ns, the output resistance less than 94? and the linearity almost good.

A New Zero-Voltage-Switching Push-Pull Converter

A soft switching three-transistor push-pull(TTPP)converter is proposed in this paper. The 3rd transistor is inserted in the primary side of a traditional push-pull converter. Two primitive transistors can achieve zero-voltage-switching (ZVS) easily under a wide load range, the 3rd transistor can also realize zero-voltage-switching assisted by leakage inductance. The rated voltage of the 3rd transistor is half of that of the main transistors. The operation theory is explained in detail. The soft-switching realization conditions are derived. An 800 W with 83.3 kHz switching frequency prototype has been built. The experimental result is provided to verify the analysis.

Determining the influence of ferroelectric polarization on electrical characteristics in organic ferroelectric field-effect transistors

Organic ferroelectric field-effect transistors （OFeFETs） are regarded as a promising technology for low-cost flexible memories. However, the electrical instability is still a critical obstacle, which limits the commercialization process. Based on already established models for polarization in ferroelectrics and charge transport in OFeFETs, simulation work is performed to determine the influence of polarization fatigue and ferroelectric switching transient on electrical characteristics in OFeFETs. The polarization fatigue results in the decrease of the on-state drain current and the memory window width and thus degrades the memory performance. The output measurements during the ferroelectric switching process show a hysteresis due to the instable polarization. In the on/off measurements, a large writing/erasing pulse frequency weakens the polarization modulation and thus results in a small separation between on- and off-state drain currents. According to the electrical properties of the ferroelectric layer, suggestions are given to obtain optimal electrical characterization for OFeFETs.

Comparative Performance Evaluation of Large FPGAs with CNFET-and CMOS-based Switches in Nanoscale

Routing resources are the major bottlenecks in improving the performance and power consumption of the current FPGAs. Recently reported researches have shown that carbon nanotube field effect transistors(CNFETs) have considerable potentials for improving the delay and power consumption of the modern FPGAs. In this paper, hybrid CNFET-CMOS architecture is presented for FPGAs and then this architecture is evaluated to be used in modern FPGAs. In addition, we have designed and parameterized the CNFET-based FPGA switches and calibrated them for being utilized in FPGAs at 45 nm, 22 nm and 16 nm technology nodes.Simulation results show that the CNFET-based FPGA switches improve the current FPGAs in terms of performance, power consumption and immunity to process and temperature variations. Simulation results and analyses also demonstrate that the performance of the FPGAs is improved about 30%, on average and the average and leakage power consumptions are reduced more than 6% and 98% respectively when the CNFET switches are used instead of MOSFET FPGA switches. Moreover, this technique leads to more than 20.31%smaller area. It is worth mentioning that the advantages of CNFET-based FPGAs are more considerable when the size of FPGAs grows and also when the technology node becomes smaller.

基于模拟开关的放大器非线性失真电路设计

非线性失真是影响模拟电路性能的重要因素之一,针对顶部失真、底部失真、双向失真和交越失真四种非线性失真情况对晶体管放大电路的影响,在详细介绍非线性失真原因及总谐波失真量化评价的基础上,以STM32F103ZET6单片机为核心,设计制作了一个放大器非线性失真研究装置。该装置主要包括晶体管放大器、采集测量、微控制器等硬件电路和软件驱动。通过两级负反馈共射放大、乙类放大分别实现基本晶体管放大和四种非线性失真产生电路,利用BL1551和CD4053模拟开关控制波形输出,采用FFT算法提取总谐波失真值。经系统测试:所设计的装置可以输出不失真波形、四种非线性失真电压波形和测量显示总谐波失真系数;测试外接信号源指定信号的总谐波失真系数时,平均精度可达95%。

SiC MOSFET开关瞬态解析建模综述

在评估和优化半导体器件开关瞬态特性领域,解析模型因具有简单、直观、应用便捷等优点得到广泛研究。相较同等功率等级的硅基功率器件,碳化硅(silicon carbide,SiC)金属氧化物半导体场效应晶体管(metal-oxide-semiconductor field effect transistor,MOSFET)可以应用于更高开关速度,其开关瞬态特性更为复杂,开关瞬态解析建模也更加困难。该文总结现有的针对SiC MOSFET与二极管换流对的开关瞬态解析建模方法,在建模过程中依次引入各种简化假设,按照简化程度由低到高的顺序,梳理解析建模的逐步简化过程。通过对比,评估各模型的优缺点以及适用场合,对其中准确性、实用性都较强的分段线性模型进行详细介绍;之后,对开关瞬态建模中关键参数的建模方法进行总结与评价;最后,指出现有SiC MOSFET开关瞬态解析模型中存在的问题,并对其未来发展给出建议。

SiC MOSFET测试系统设计与开关特性分析

以碳化硅金属-氧化物半导体场效应晶体管(SiC MOSFET)为代表的第3代半导体功率器件因其优异的开关特性,在新能源等领域被广泛应用,但面对高速开关耦合寄生参数所产生的负面效应,使得测试系统难以快速、准确评估其开关瞬态等相关参数。首先,根据改进的双脉冲模型设计了一种高精度测试系统,硬件主要包括功率测试板、集成脉冲发生器的控制板及驱动板,软件主要利用Keil编写控制板程序,LabVIEW进行用户界面设计。其次,还探讨了电压和电流测量技术、连接技术和测量数据的处理,并且结合器件数据手册及仿真结果分析实测结果,表明该系统测量误差小,量程大,抗干扰能力强,可信度高,能为优化第3代半导体器件和驱动电路的设计和应用提供有益支持。

一种半桥LLC高压电源设计与实现

设计一种基于半桥LLC谐振变换器的高压电源,其基本结构包括逆变电路、谐振电路、倍压整流电路和反馈控制电路,可用于微波功率模块集成电源。为实现高压电源的高效率,详细分析了半桥LLC谐振电路中场效应管零电压开启的实现条件,并给出了实现该条件所需电路关键参数的计算方法。通过计算机仿真辅助优化电路参数,降低了场效应管和变压器的损耗。最后,研制了一台高压电源原理样机,其输出电压为-3000 V,满载输出功率为300 W,在245~300 V输入电压范围内效率大于96%,峰值效率为97.5%。

不同封装结构SiC MOSFET的开关振荡分析

此处分析了不同封装结构碳化硅金属-氧化物半导体场效应晶体管(SiC MOSFET)在开关过程中振荡的产生原因和影响因素。首先建立简化电路模型,准确计算出开关稳态后电压振荡的时域表达式,该电路模型考虑了器件的相关性能参数、器件和电路中的寄生参数。其次通过Matlab软件对模型中的时域表达式进行波形拟合。最后搭建了双脉冲测试平台,实验验证了模型的精确性,也具体量化了不同参数对开关振荡的影响。

基于GaAs E/D PHEMT工艺的Ku波段双通道幅相控制多功能芯片

基于GaAs增强/耗尽型赝配高电子迁移率晶体管(E/D PHEMT)工艺设计了一款14~18 GHz的双通道多功能芯片。芯片集成了单刀双掷(SPDT)开关、6 bit数控移相器、4 bit数控衰减器和增益补偿放大器。采用正压控制开关以减小控制位数;优化移相、衰减和放大等电路拓扑结构,以获得良好的幅相特性;采用紧凑布局、双通道对称的版图设计,以实现小尺寸和高性能。测试结果表明,+5 V电压下,接收通道增益大于3 dB,1 dB压缩点输出功率大于8 dBm;发射通道增益大于1 dB,1 dB压缩点输出功率大于2 dBm;64态移相均方根误差小于2.5°,16态衰减均方根误差小于0.3 dB,芯片尺寸为3.90 mm×2.25 mm。该多功能芯片可实现对射频信号幅度和相位的高精度控制,可广泛应用于微波收发模块。

基于各向异性导电膜的射频SP8T开关无损测试

为了解决射频器件无损测试的难点,基于各向异性导电膜Z轴(ACF-Z)连接结构,设计并实现了射频器件无损测试技术。针对表面贴装式GaAs金属半导体场效应晶体管(MESFET)单刀八掷(SP8T)开关,该测试技术使用ACF-Z轴连接结构实现器件与测试板的无损连接,通过矢量网络分析仪对GaAs MESFET SP8T开关性能进行测试,最多可同时测试SP8T开关的8个通道。测试结果显示,1~8 GHz内,器件的插入损耗为-15~-35 dB,回波损耗为-15~-35 dB,测试过程中未对器件造成损伤。

一种低电压、高增益电荷泵

电荷泵在低压电路中扮演着重要的角色。作为片上电荷泵,其面临的主要问题是:电压增益、电压纹波和面积效率。该文提出了一种新型的电荷泵电路,它采用辅助电荷泵、电平转移电路结构来产生不同摆幅的时钟,该时钟被用来驱动开关管的栅极,以有效控制开关管的电导,提高电压增益。由于采用PMOS管作为开关管,传输过程中避免了阈值电压损失。仿真结果显示,与以往文献中提到的电荷泵结构相比,该电荷泵具有更高的电压增益,开启时间短,纹波小,在低压应用环境优势更为突出。

电火花精微加工脉冲电源设计

设计了一种脉冲能量可控、附有消电离环节的新型电火花精微加工脉冲电源，利用一个开关管控制电容器的充电过程，另一个开关管控制放电过程，提高了加工效率。

一种新型高功率因数软开关电源

提出了一种新型高功率因数软开关小功率电源的设计方法,讨论了基于ML4803芯片控制的功率因数校正电路及无源无损的软开关DC/DC变换器。DC/DC变换部分采用了新颖的双管正激软开关技术,在不使用辅助开关管的情况下实现了开关管的零电压开通和关断,并成功研制了48V/10A的实用小功率电源模块,使其具有动态响应快、高功率因数、高效率及体积小等优点。

采用高能电子束辐照技术制造高反压大功率开关晶体管

应用最佳能量为１２ＭｅＶ的电子束对大功率开关晶体管进行了辐照．结果表明，经电子束辐照的开关晶体管具有开关特性优良、热稳定性高、器件参数一致性好等特点。

推挽正激DC/DC变换器的研究与实现

针对推挽电路DC/DC变换器中的开关管电压尖峰高、高频变压器偏磁等问题,设计了基于推挽正激技术的DC/DC变换器。通过对推挽正激电路工作原理的分析,设计了主功率电路和辅助电路;并对以往典型DC/DC电路中变压器参数与设计需求不符、设计繁琐难以掌握等重点问题进行了研究,采用了清晰明了的变压器设计过程及关键参数的计算方式。试验表明,该变换器具有外围电路简单、效率高、成本低廉等优点。