一种MHz光耦隔离放大器的设计与分析

本文设计了一种基于高线性度高带宽模拟光耦HCNR201芯片的MHz光耦隔离放大器电路,主要应用于计算机数据采集系统中,对其信号进行隔离从而实现过电压保护和提高共模抑制比.HCNR201光耦器件具有双光电二极管结构,使电路在输入端构成反馈环节,消除了光耦的电流传输比对直流增益的影响,为了方便分析建立了它的等效电路.利用线性控制系统的理论方法建立了所设计的隔离放大器电路的数学模型,推导出了电路的传递函数,对电路进行了理论分析和参数优化,并给出了分析设计结果.同时研制了隔离电路并对其进行了实验测试,实验结果与理论分析结果比较一致,符合设计要求,其理论分析方法可以为类似电路设计提供参考.     

A five-terminal plus or minus 15-V monolithic voltage regulator

A five-terminal /spl plusmn/15-V monolithic voltage regulator has been developed that incorporates internal frequency compensation and internally provides a /spl plusmn/1 percent output voltage tolerance. In addition, a thermally symmetric layout design of the chip has been used to eliminate the detrimental effects of thermal feedback on the die and ensure that the complementary tracking output voltages will be independent of the power dissipation in the series pass power transistors. Complete fault protection is accomplished by providing the power transistors with good dc safe operating area, internally limiting the short circuit output currents, and accurately limiting the junction temperature to within 10/spl deg/C of the specified maximum limit. Also, a new Zener diode geometry is employed that significantly reduces the noise associated with the reference voltage.     

New Edge-Guided Mode Isolator Using Ferromagnetic Resonance Absorption

A new edge-guided (EG) mode isolator is described in which nonreciprocal attenuation is due to the ferromagnetic resonance absorption caused by a strong dc magnetic field applied locally at the short-circuited edge of a ferrite microstrip line. From modal analysis, including the magnetic losses of ferrite substrate and the transversal variation of the internal dc magnetic field, the dominant EG mode has been proved to propagate along not only the conventional ferrite stripline but also a stripline with one edge short circuited to the ground. Dispersion relations and RF electric field distribution have been calculated numerically, and the upper limit of isolator bandwidth has been discussed with several design parameters. Based on the results, a practical EG mode resonance isolator has been successfully developed, which has more than 25 dB isolation loss and less than 1.0 dB insertion loss over a 4.0-8.0-GHZ frequency band throughout the - 10/spl deg/C-+60/spl deg/C temperature range,     

Step-by-step design procedure for a grid-connected three-phase PWM voltage source converter

The voltage source active rectifier is one of the most interesting solutions to interfacing dc power systems to the grid. Many elements are responsible for the overall system behaviour, such as value of the passive elements, sensors position, analog/digital filters and ac current/dc voltage controllers. In this paper a step-by-step design procedure, taking into account all these elements, is proposed and validated through the tests on an experimental prototype. The reported results are particularly relevant to evaluate the influence on the grid current harmonic content of the grid sensor position and of the use of analog filters in the feedback signals.     

基于UC3844的反激式开关电源设计

电源的优劣直接影响到各类电子设备的性能,文中设计了一款性能优良的开关电源。该电源控制电路以UC3844为核心进行设计;DC/DC变换主电路采用单端反激式电路;电源电压反馈部分采用典型的TL431加光耦PC817。实验结果表明该电路效率高,输出稳定,性能优越,成本相对较低。     

Temperature dependence performances of fully integrated DC SQUID magnetometers

Temperature dependence of the main characteristics of integrated dc superconducting quantum interference device magnetometers based on niobium technology including an additional positive feedback circuit is reported. Temperatures above 4.2 K have been considered. A nonlinear temperature dependence of the spectral density of the field noise has been observed. The reported measurements show a slow increasing of the field noise up to temperatures of about 5 K, giving a considerable tolerance of the working temperature of niobium magnetometers in some innovative multichannel systems for magnetoencephalography.     

Modeling and Performance Analysis of the DC/DC Series–Parallel Resonant Converter Operating With Discrete Self-Sustained Phase-Shift Modulation Technique

A dynamic study of the dc/dc series–parallel resonant converter operating with a discrete self-sustained phase-shift modulation technique is presented. The study includes the synthesis of a suitable averaged large-signal dynamic model and the design of a nonlinear feedback controller based in the input–output linearization approach. The proposed controller and modulation type provide some outstanding features: zero-voltage switching operation for the whole load range, narrowed frequency variation range, fast transient response, and robustness in relation to external parameter variations. Experimental and simulation results are reported to validate the theoretical predictions and confirm the superior performance of the nonlinear controller when it is compared with a conventional linear controller.      

高压隔离高线性度光电耦合器

研制了一种高压隔离高线性度光电耦合器.采用混合集成技术,在6DIP陶瓷管座内成功制作出了高压隔离线性光电耦合器.叙述了该器件的工作原理、工作特性及设计考虑,并在在此基础上进行了实验,实验结果表明此器件具有结构简单、精度高、线性度好的优点.     

Investigation of optical feedback in high-speed electroabsorption modulated lasers with a window region

The optimum waveguide design for optical feedback reduction in a 10-Gb/s electroabsorption modulated laser has been discussed. A device with a 30-/spl mu/m-long window region exhibited as much as 10-15-dB reduction, which is verified by experimental results and the beam propagation calculation. Using a tilted waveguide with the window region, the feedback factor is reduced to as low as -40 dB. Besides low optical feedback, the tilted-and-straight modulator has a sufficient dc extinction ratio and a far-field profile allowing larger than 60% fiber-coupling efficiency.     

Hard Magnetic Dots for Flux Bias of DC SQUIDs

In this paper, we demonstrate that perpendicularly magnetized sub- and micrometer-sized magnetic dots, with a high coercivity and nearly complete remanence, can be used to provide the flux bias for dc superconducting quantum interference devices (SQUIDs). The radius of a submicrometer Co–Pd magnetic dot has been optimized with respect to the surrounding superconducting circuitry to generate the phase shift of approximately$pi/2$in it. In this way, it is possible to bias a dc SQUID to the steepest part of its voltage-flux characteristic without using an additional coil and current source. Furthermore, it has been shown that the flux bias can also be achieved using a micrometer-sized Co–Pd dot, upon saturation, by placing a dc SQUID on top of the dot. Given that the underlying principles of flux biasing do not require any particular superconducting pairing scheme (s- or d-wave), these hybrid superconductor/ferromagnet structures can be used as to design a dc SQUID with a complete flux self-biasing.     

Nonlinear Feedback Control of a Bearingless Brushless DC Motor

The demands on bearingless drive configurations concerning performance as well as costs are high. The proposed bearingless brushless dc motor consists of five concentrated coils in a symmetrical arrangement, which generate radial forces and motor torque simultaneously in interaction with a permanent-magnet-excited disk-shaped rotor. Additionally, tilting deflection and the axial position of the rotor are stabilized passively by means of magnetic reluctance forces. Thus, system costs can be reduced significantly compared to a conventional bearingless motor setup, which actively stabilizes all 6 DOF. Due to the nonlinearity of the plant, the use of linear control design methods alone is not suitable for achieving a high operation performance. This paper introduces a novel radial position and motor torque control algorithm for a bearingless brushless dc motor based on the theory of feedback linearization. Thereby, the combined model of translatory and rotatory dynamics can be split into independent linear systems by means of a nonlinear change of system coordinates and a static-state feedback. Experimental results demonstrate the effectiveness of the proposed approach.      

An Electronically Tunable Linear or Nonlinear MOS Resistor

We present a bidirectional MOS resistor circuit that is electronically tunable and has zero dc offset. For a given I–V characteristic, the circuit senses the source-to-drain potential across an MOS device and automatically generates an appropriate bias for the gate terminal to implement the characteristic via negative feedback. We show that the I–V characteristic of the resistor can be designed to be linear, compressive or expansive by using appropriate translinear current mode circuits for the feedback biasing. Our technique does not require the MOS transistor to operate in the triode region and is valid in both weak and strong inversion. Experimental results from a CMOS process show that a square-root, linear, or square resistor can be implemented as examples of our topology. The linear version was tunable over a resistance range of 1 ${hbox{M}}Omega$ –100 ${hbox{G}}Omega$ in our particular implementation and exhibited proportional-to-absolute temperature (PTAT) behavior. The measured excess noise of the resistor agrees with theoretical predictions.      

数字信号光耦合器应用电路设计

较强的输入信号可直接驱动光耦的发光二极管,较弱的则需放大后才能驱动光耦。在光耦光敏三极管的集电极或发射极直接接负载电阻即可满足较小的负载要求;在光耦光敏三极管的发射极加三极管放大驱动,通过两只光电耦合器构成的推挽式电路以及通过增加光敏三极管基极正反馈,既达到较强的负载能力,提高了功率接口的抗干扰能力,克服了光耦的输出功率不足的缺点,又提高光耦的开关速度,克服了由于光耦自身存在的分布电容,对传输速度造成影响。最后给出了光耦合器在数字电路中应用示例。     

Thermal incremental equivalent circuits of integrated circuit devices

A procedure of thermal stability design of integrated-circuit devices, based on the use of thermal incremental equivalent circuits, is described. These circuits may be derived by inspection from the dc equivalent circuit. They offer insight into the interdependence of various components in determining temperature variations and simplify the conventional analysis.     

A Three-Level Full-Bridge Zero-Voltage Zero-Current Switching Converter With a Simplified Switching Scheme

Multilevel dc–dc converters making use of high-frequency transformers are suitable for integration in solid-state solutions for applications in electric power distribution systems. This paper presents a simplified switching scheme for three-level full-bridge dc–dc converters that enables zero-voltage and zero-current switching of all the main power devices. It describes the main operational modes and design equations of the converter as well as provides simulation and experimental results to demonstrate the feasibility of the proposed ideas.      

Theoretical Analysis of the Operation of the Field-Displacement Ferrite Isolator

A theoretical analysis of the resistance-sheet isolator is carried out, and numerical solutions are obtained for the forward and reverse propagation constants of the distorted dominant mode in a rectangular waveguide containing a transversely magnetized thick ferrite slab displaced slightly from the side wall. The microwave electric field patterns within the waveguide are plotted for several values of the physical design parameters of the isolator for which experimental performance data have been reported. Field patterns are used to describe the principles of the isolator and to select the optimum values of slab thickness, internal dc magnetic field, ferrite magnetization, and location of the slab in the waveguide for the idealized isolator. Evidence is presented to show that it is necessary to use a comparatively thick ferrite slab located in a very small usable range of distances from the side wall. The appropriate value of internal dc magnetic field is simply related to the magnetization of the ferrite and to the frequency. It has not been necessary to take into account the perturbing effects of the resistance card or matching techniques in order to explain the basic design principles.     

一种抗辐射加固小功率开关电源的设计

介绍了一种隔离型抗辐射加固小功率开关电源的设计,重点介绍了CMOS脉宽调制器的抗中子、总剂量措施和变压器的设计。电路采用单端反激、磁隔离反馈工作方式;通过线路补偿和工艺上的加固设计,使电路的抗辐射水平达到要求。辐照测试结果证明了设计的正确性。     

Total dose response studies of n-channel SOI MOSFETs for low power CMOS circuits

Key building blocks – simple ternary inverter, positive ternary inverter and negative ternary inverter have been designed for operation at a low voltage – ±1 V in 2 μm, n-well standard CMOS process and simulated in SPICE3 for use in the design of ternary logic circuits. The back-gate bias method has been used in conjunction with the width/channel (W/L) ratio of MOSFETs to generate the desired dc voltage transfer characteristics and transition region adjustment around midway between high and low logic levels.     

线性光耦HCNR201原理及其在轴承故障检测中的应用

因铁路货车轴承故障检测现场工况复杂,各种电磁干扰信号极易随被测信号进入测量系统.针对这个问题,设计了用高线性度模拟光耦HCNR201和运算放大器实现的电压隔离硬件电路.该电路中,线性光耦的前端用一个运算放大器构成一个负反馈放大器,用来检测模拟电压信号;线性光耦后端的运算放大器进行电流与电压之间的转换,最终输出电压信号,实现电压信号的1：1隔离传输.实验结果表明：该方法测量电压线性度好、精度高.