一种高精度数字可调RC振荡器设计

在对常见的RC振荡器进行分析比较的基础上,提出了一种高精度的RC振荡器。对其进行温度补偿的改进,并采用数字修调方式实现频率微调以消除电源及工艺带来的误差,双比较器对称性结构设计有效的消除了比较器迟滞带来的频率误差。利用CSMC的0.5μm工艺Bsim3模型和Hspice仿真器对该电路进行了模拟和仿真,结果表明该电路与传统的振荡器相比具有精度高、误差可调的优点。最后对该电路进行版图设计。     

一种新型高精度RC振荡器电路设计

在对传统的振荡器电路的分析比较基础上,基于振荡器的基本工作原理,结合误差比较器技术,提出了一种新型高性能低功耗的RC振荡器.利用CSMC的DPDM Bsim3模型和Cadence的Spectre仿真器对该电路进行了模拟和仿真,结果表明该电路与传统的振荡器相比具有精度高、功耗低的优点.最后对该电路进行版图设计,版图面积为70.5×62.59μm2.     

一种应用于MCU的低温漂RC振荡器设计

针对高稳定性MCU的应用需求,设计了一种低温度灵敏度的RC振荡器.采用平均电压反馈电路降低比较器延迟对振荡器输出频率的影响,采用温度补偿技术补偿温度对振荡器输出频率的影响,实现RC振荡器高稳定性输出.设计了一种选频网络,实现宽频率范围内高精度输出,满足MCU对多种时钟频率的需求.RC振荡器基于SMIC 110 nm C...     

一种基于斩波拓扑的高精度RC振荡器

设计了一种采用0.18μm CMOS工艺制作的基于斩波拓扑的高精度RC振荡器。该结构对比较器失调有较好的抑制效果,并补偿了比较器传输延时对输出时钟频率的影响,达到了较好的温度特性。同时使用LDO对振荡器的主体电路供电,有效抑制了电源电压波动对输出频率的影响。另外该振荡器使用电容修调网络,减小了工艺漂移对中心频率的影响。仿真结果表明,所设计的振荡器在不同工艺角下均可以通过修调将频率校准至典型值2 MHz。在-40～125℃的温度范围内,输出频率的波动仅为0.87%。在3～6 V的电源电压范围,输出频率的波动仅为0.21%。与同类型的片上RC振荡器相比,该电路对温度、电源电压和工艺的漂移有更好的抑制作用。     

一种无比较器的高精度RC振荡器设计

基于华虹0.18μm CMOS工艺，设计了一种无比较器的低温漂高精度RC振荡器。通过调整电流源的负温度系数电流补偿MOSFET阈值电压的温漂，保证输出频率在大温度范围内的高稳定性。通过提高电流源输出阻抗，提高振荡器的电压稳定性。采用数字修调技术矫正工艺偏差引起的频率误差。该振荡器由启动电路、CTAT电流源电路、电流镜电路、修调电路、竞争冒险消除电路和RC振荡电路六部分构成。因为没有采用比较器结构，所以在该振荡器中，不会出现由于比较器的传输延时与输入失调电压引起的非理想因素。采用Cadence进行电路仿真与验证，后仿真结果表明，该振荡器的典型频率为2 MHz,起振时间为5.1μs。在3～5 V电源电压变化范围内，频率偏差均在±0.55%以内；在-40～125℃温度范围内，输出频率随温度的变化率均在±1.2%以内，可适用于高精度的数模混合信号芯片。     

带辅助RC电路的非对称多谐振荡器

这篇论文论述了非对称多谐振荡器的设计。这些多谐振荡器包括一个由电流源充电,用比较器控制开关周期性地放电的大电容器。这些多谐振荡器的独特之处在于带有一个小时间常数的辅助RC电路,连接在大电容器与比较器之间。辅助RC电路的输出电压在第一个暂稳态期间(space)跟踪大电容器的电压。辅助RC电路中的小电容重新充电用来决定第二个暂稳态的持续时间(mark),同时讨论了三种变型电路。如果空度比(space/mark)较小(～10),要在大电容器和辅助RC电路之间插入附加的缓冲放大器。对空度比为中等值的多谐振荡器,缓冲放大器被省掉,辅助RC电路中的电容器并入大电容器(也能被省略)。对空度比大的(～1000),辅助RC电路被直接联接到大电容器上。本文给出了两个暂稳态的计算方法和有用的设计关系式,给出一个对不同空度比(9.99和999)多谐振荡器的例子。     

一种新型电容修调RC振荡器

为了降低RC振荡器的功耗,并提高振荡频率的稳定性,提出一种新型的RC振荡器电路。该振荡器采用单比较器,结合电容修调结构。基于0.35 μm BCD工艺及Hspice 仿真工具,完成了电路的设计和仿真,仿真结果表明,该振荡器正常工作频率为51 kHz,由于温度和电源电压变异,频率变化范围为47.54~53.97 kHz,最大功耗电流为2.1 μA,面积为150 μm×180 μm,具有较低的功耗,可以提供相对稳定的频率,能够应用于电源管理芯片。     

适用于数字电源的新型温度自校准片上振荡器的设计

设计了一种应用于数字电源的新型温度自校准高精度片上振荡器。该振荡器利用片内集成的环形振荡器作为"温度传感器",环形振荡器的偏置电流设计成与热力学温度成正比,输出时钟信号频率对温度变化高度敏感,以此作为温度校准的参考信号,经过数字自校准算法产生控制RC振荡器充电电流大小的信号,校准RC振荡器输出时钟频率,从而完成片上实时温度自校准的功能。采用双比较器加SR触发器对称结构,降低比较器延迟误差。电路基于0.18μm BCD工艺模型,采用Cadence和Hspice进行仿真。仿真结果表明,在–55~+155℃温度范围内,振荡器输出中心频率为10.1 MHz,振荡器的频率随温度变化的偏移量在±0.6%以内。     

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.     

消费类芯片RC振荡器的分析与设计

市场竞争的压力使得人们不得不在成本和性能间寻找一个令人满意的折衷.振荡器的选择也是如此,在晶振、环形振荡器和RC振荡器中,RC振荡器具有面积小,成本低,频率可调等优点适合于消费类电子等对频率稳定性要求不高的领域.本文先分析简单的多谐RC振荡器,然后介绍一种性能更优的,基于比较器结构的RC振荡器的设计.并给出了设计中需要注意的问题,以及流片后实际的测量数据.     

Dual-stage repetitive control with Prandtl–Ishlinskii hysteresis inversion for piezo-based nanopositioning

The positioning performance of piezo-based nanopositioning systems is limited by dynamic and hysteresis effects in the piezoactuator. Herein, a high-performance, dual-stage repetitive controller (dual-RC) with a feedforward hysteresis compensator is proposed for tracking periodic trajectories, such as the scanning-type motion, in nanopositioning systems. Firstly, a discrete-time dual-RC is created by cascading a conventional RC with an odd-harmonic RC. The favorable gain characteristics of the dual-RC coincide with the odd harmonics of the scanning-type periodic reference trajectory, thus offering good robustness and low tracking error. Secondly, a new inverse-hysteresis compensator is developed based on the Prandtl–Ishlinskii hysteresis model. The structure of the inverse model mimics the structure of the forward model, where the parameters of the inverse model can be easily identified from measured input–output data. Finally, the controllers are applied to a custom-designed high-speed nanopositioner, and simulations and experimental results are provided to illustrate the performance improvement of the proposed control scheme compared to industry-standard PID control and conventional RC. High-speed positioning results (tracking of triangle scan trajectories) at rates of 1 kHz, 1.5 kHz, and 2 kHz are shown. Compared to a conventional RC, the tracking error of the dual-RC is 48% lower at 1 kHz and 33% lower at 2 kHz scanning frequency. It is also shown that by compensating for hysteresis, the performance of the RC system designed based on the linear dynamics can be enhanced.     

A MOS LSI capacitive keyboard interface chip

A single chip silicon gate LSI device is described which interfaces a microprocessor to a capacitive keyboard. The LSI circuit replaces a large number of MSI devices and substitutes a unique digital key detection scheme for the more traditional differential amplifiers. On chip are an internal oscillator, a clock generator, key matrix scanning and detection circuits, a digital filter, input sensing circuits with hysteresis, multiple key rollover electronics, and handshaking logic to interface asynchronously with any standard 8-bit microprocessor such as the 8080. Off chip is only an RC network for the purpose of setting the oscillator frequency.     

互连线RC模型应用条件的仿真研究

研究结果表明,在L与RC比值较小时,阶跃响应的上升时间基本上由RC的乘积决定,电感对电路的影响可以忽略,互连线采用RC模型与RLC模型结果应无多大差别。在L与RC比值较大时,阶跃响应曲线出现振荡,此时使用RC模型需满足工作频率低于RC模型的“上限使用频率;当工作频率超过RC模型的“上限使用频率”时,互连线的模型就必须采用RLC模型。RC模型的“上限使用频率”仅与互连线长度有关:fmax106(Hz·m)。     

Analysis and prediction of inverter switching frequency in directtorque control of induction machine based on hysteresis bands andmachine parameters

In this paper, the influences of the hysteresis bands on the direct torque control (DTC) of an induction motor are analytically investigated, and the switching frequency of the inverter is predicted based on the analysis. The flux and torque hysteresis bands are the only gains to be adjusted in DTC, and the inverter switching frequency and the current waveform are greatly influenced by them. Therefore, the magnitude of the hysteresis band should be determined based on reasonable guidelines which can avoid excessive inverter switching frequency and current harmonics in the whole operating region. This paper predicts the inverter switching frequency according to torque and flux hysteresis bands based on induction machine parameters and control sampling period, and investigates the effect of hysteresis bands to line current harmonics. The simulated and experimental results prove the usefulness and feasibility of the proposed method     

Analysis of high speed p-i-n photodiode S-parameters by a novel small-signal equivalent circuit model

A novel small-signal radio frequency (RF) equivalent-circuit of the side-illuminated input tapered waveguide-integrated p-i-n photodiodes (WG PIN PD) is proposed. The proposed RF equivalent-circuit involves both the carrier-transit effect and the external resistance-capacitance (RC) time constant limitation on the frequency response of the p-i-n PD. The carrier-transit effect is realized by adding an RC circuit to an ideal voltage-controlled current source as the input opto-RF equivalent circuit. The carrier transit-time effect is equivalently represented by the time-constant of this input RC circuit. This new equivalent circuit model fits well with both the measured reflection and optoelectronic conversion parameters of the WG PIN PD in a broad frequency range from 45 MHz to 50 GHz.     

Frequency response and modeling of resonant-cavity separateabsorption, charge, and multiplication avalanche photodiodes

A theoretical model incorporating the mechanism of resonant absorption of the multiple reflected lightwaves is presented for the frequency response of resonant-cavity (RC) separate absorption, charge, and multiplication (SACM) avalanche photodiodes (APDs). The derived theoretical expressions are general and can be readily applied to many other RC and non-RC APDs. These analytical expressions also allow for fast computation of the frequency response and bandwidth characteristics. Combining this frequency response theory with expressions of multiplication gain and ionization coefficients, an efficient approach is proposed for modeling the general performance characteristics of RC APDs. The modeling approach is applied to an InGaAs-AlGaAs RC SACM APD. The computed results are demonstrated, and the results of -3 dB bandwidth are comparable to experimental work. The validity of the modeling parameters is also discussed. It is further found that the normalized frequency response is unaffected when the value of the absorption coefficient is changed, suggesting that the standing-wave effect within the RC structure may not influence the bandwidth characteristics     

Chaoticity of a Reverberation Chamber Assessed From the Analysis of Modal Distributions Obtained by FEM

Wave chaos theory is used to study a modeled reverberation chamber (RC). The first 200 modes at a given stirrer position are determined by the finite element method, and the Weyl formula is checked for various RC geometries, from integrable to chaotic. The eigenfrequency spacing distribution varies according to the degree of ray chaos in the RC related to its geometry. The eigenmode distributions are also analyzed and compared to the theoretical Gaussian distribution: close to the lower useable frequency, the modes of the studied chaotic RC fairly respect this asymptotic property. A general result of chaotic systems is illustrated: when perturbed by the stirrer rotation, the resonant frequencies of a chaotic RC avoid crossing. This implies that the frequency sweeps tend to vanish at high frequency.     

磁滞及磁饱和效应对磁光光纤传感器的影响

给出了ＩｎＢｉＣａＶＩＧ晶体的磁滞回线,详细分析了磁滞及磁饱和效应对磁光光纤传感器的影响。当所测磁场信号为交变量时,磁滞的影响主要是相位延迟,对幅度及频谱分布影响较小;饱和效应不仅使响应幅值减小,同时还导致明显的频谱变化。     

Sequential design of hysteresis current controller for three-phaseinverter

In this paper, a novel multivariable hysteresis current controller for three-phase inverters is presented. Hysteresis controllers are intrinsically robust to system parameters, exhibit very high dynamics, and are suitable for simple implementation. The main drawback of the hysteresis controller is a limited control on transistors' switching frequency. Very high switching frequency may result if three independent controllers are used. Multivariable solutions were proposed in the literature to solve the problem. In this paper, it is shown how the use of a sequential design for the multivariable controller can further contribute to transistors' switching frequency reduction, with no significant increase in the hardware implementation complexity. The proposed controller is illustrated and compared with other hysteresis controllers presented in the literature. It ensures a significant reduction of transistors' switching frequency with respect to the other tested controllers, under the same operating conditions. A prototype controller is also presented. The effects of noise captured by current sensors (especially Hall-effect type) on the performance of industrial hysteresis controllers are discussed. It is shown how the sequential design of the controller can also help in solving this critical problem. Experimental results are reported to confirm the quality of the proposed controller. The system stability condition is derived in an appendix     

应用Multisim进行无源RC电路的时频分析

＂电路分析基础＂是高等院校电气信息类专业的一门重要的基础课,本文应用Multisim对无源一阶RC电路的时域特性和频域特性进行了仿真分析,构建了RC微分电路、RC积分电路、一阶RC低通电路和一阶RC高通电路的仿真演示示例。通过仿真演示,使学生加深对RC电路内容的理解和掌握。