单片弛张振荡器的温度补偿方法

介绍单片弛张振荡器的工作原理,分析弛张振荡器产生输出频率误差的原因及温度对输出频率的影响,推导出振荡器达到零温度系数的条件,提出一种弛张振荡器内温度补偿方法,只要在设计电压基准源的温度系数时结合振荡器的需要来考虑,利用该方法就可以使弛张振荡器方便地获得较好的温度系数,大大缩小面积和降低成本.最后给出仿真波形.     

一种超低功耗RC振荡器设计

基于SMIC 55 nm CMOS工艺,设计并制备了工作在1.2V电源电压下的超低功耗RC振荡器.该振荡器主要包括运算放大器、压控振荡器(VCO)、基准电流源、低温漂电阻和可修调开关电容以及非交叠时钟产生电路.该振荡器用工作在亚阈值区的运算放大器和VCO取代了传统单比较器型RC振荡器中的比较器,显著降低了功耗;用开关电容取代了充放电电容,并且将输出时钟的频率转换成了阻抗,与参考电阻进行比较.利用负反馈环路锁定了输出时钟信号频率,从而得到了稳定的时钟信号.测试结果表明,1.2V电源电压、27℃环境下,该RC振荡器的输出时钟信号频率为32.63 kHz,功耗为65 nW;在-10 ～ 100℃,其温度系数为1.95×10-4/℃;在0.7～1.8 V电源电压内,其电源电压调整率为3.2％/V.芯片面积为0.168 mm2.     

一种基于0.5μmCMOS工艺的补偿型电流控制振荡器设计

提出了一种基于比较器的CMOS电流控制振荡器电路,该振荡器采用偏置电流对电容充放电,产生精准锯齿波,比较器及后续电路产生时序方波作为比较器输入,从而产生周期振荡.自偏置电路利用电阻和PNP管相反的温度系数产生PTAT、NTAT两路电流,叠加得到一路与温度无关的基准电流、实现了温度补偿;高摆幅共源共栅电流镜结构具有高PSRR实现了电源电压补偿.本设计采用0.5 μmCMOS工艺,典型情况下,振荡器频率为1.224 MHz,占空比为50%,通过spectre仿真结果表明:该振荡器在3.3 V～5 V的工作电压下、-40～120℃温度范围内都具有较好的工作频率.     

一种高精度高稳定性的片内振荡电路设计

作为系统时钟源,振荡电路的频率特性会影响芯片工作性能。为提高片内振荡器输出时钟的精度及稳定性,设计一种基于RC结构的振荡电路。该振荡电路采用带隙基准产生电容充电电流及基准电压,通过调整镜像管比例进行频率粗调校正,通过调整基准电压大小和温度系数以实现频率细调校正及温度特性校正。电路基于55 nm CMOS工艺设计实现,仿真结果表明,典型条件下电路工作输出为30 MHz,50%占空比时钟,在1.6～5.5 V、-40～125℃工作范围内,振荡频率偏移位0.6%以内,中心校准精度为0.5%,可作为片内高精度时钟源或参考时钟。     

一种高精度带隙基准电压源电路设计

针对传统CMOS带隙电压基准源电路电源电压较高,基准电压输出范围有限等问题,通过增加启动电路,并采用共源共栅结构的PTAT电流产生电路,设计了一种高精度、低温漂、与电源无关的具有稳定电压输出特性的带隙电压源.基于0.5μm高压BiCMOS工艺对电路进行了仿真,结果表明,在-40℃～85℃范围内,该带隙基准电路的温度系数为7ppm/℃,室温下的带隙基准电压为1.215 V.     

一种高精度数字可调片上振荡器设计

在传统的电路基础上对电流、电压基准电路进行补偿,设计一种高精度数字可调CMOS片上振荡器电路.利用电阻和PNP管相反的温度系数产生的自偏置基准电流电路PTAT,NTAT两路电流,叠加得到一路与温度无关的基准电流上,实现了温度补偿;利用电阻网络补偿工艺产生高PSRR带隙基准电路电压的频率误差;数字修调寄存器粗调电流用以选择频率,微调电阻用以调节精度.经流片测试表明,该振荡器频率2 MHz,4 MHz可选,2 MHz可调精度达±0.1%;4 MHz可调精度达±0.125%.     

一种改进型BiCMOS带隙基准源的仿真设计

依据带隙基准原理,设计了一种基于90 nm BiCMOS工艺的改进型带隙基准源电路.该电路设置运算跨导放大器以实现低压工作,用共源-共栅MOS管提高电路的电源抑制比,并加设了新颖的启动电路.HSPICE仿真结果表明,在低于1.1 V的电源电压下,所设计的电路能稳定地工作,输出稳定的基准电压约为610 mV;在电源电压V_(DD)为1.2 v、温度27℃、频率为10 kHz以下时,电源噪声抑制比约为-45 dB;当温度为-40～120℃时,电路的温度系数约为11 × 10~(-6)℃,因此该基准源具有低工作电压、高电源抑制比、低温度系数等性能优势.     

一种高精度高稳定性锯齿波振荡器的设计

设计了一种应用于DC/DC开关电源管理芯片的锯齿波振荡器,该电路利用内部基准电流源产生的电流对电容进行充放电,使得产生的锯齿波信号随电源电压和温度的变化较小,采用迟滞技术提高了锯齿波信号幅值.采用基于CSMC的0.5μmCMOS 工艺进行仿真.结果表明,该电路产生的振荡频率为5MHz,信号幅值为0-3V,电源电压在2....     

一种输出可调CMOS带隙基准电压源的设计

传统设计中平衡温度时的带隙基准电压值是与工艺相关联的定值.主要基于通用的带隙技术讨论在CMOS工艺中基准产生的设计,在对基准产生原理与传统电路结构分析的基础上,设计出一种高PSRR输出可调带隙基准电压源.电路综合温度补偿、电流反馈和电阻分压技术,采用CSMC 0.5 tim CMOS混合信号工艺实现,并用Cadence的Spectre进行了仿真优化.仿真结果表明,带隙基准电压源在-15～80℃范围内输出为603.5 mV时的温度系数为6.84 × 10-6/℃,在1.8～5 V电路均可正常工作.流片后的测试结果验证了该方法的可行性,基准电压中心值可宽范围调整,各项性能参数满足设计要求.     

一种具有高阶温度补偿的高精度RC振荡器设计

基于当前一些高集成度高精度应用领域时钟信号大量需求的目的，介绍了一种具有高阶温度补偿的高精度RC振荡器。文中所设计的电流源电路采用了3阶温度补偿的方法，可以有效降低电路对温度变化的敏感性，利用具有超低温度系数的电流对电容进行充放电，实现在较宽的温度范围内振荡器频率的高稳定性。仿真结果表明：在电源电压范围为2.5 V～5.5 V，温度范围为-40℃～125℃，及不同的工艺角下，输出频率精度保持在±0.25%以内。该RC振荡器具有高精度的输出频率，能够作为一些数模混合电路的时钟信号。     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first