Voltage-to-frequency converter with high sensitivity using all-MOS voltage window comparator

A high-sensitivity voltage-to-frequency converter (VFC) using an all-MOS voltage window comparator is presented in this work. The circuit is composed of one voltage-to-current converter, one charge and discharge circuit, and one all-MOS voltage window comparator. The input voltage is converted into a current which in turn triggers the charge and discharge circuit, where a built-in capacitor is driven. The voltage window comparator monitors the variated voltage on the capacitor and generate an oscillated output of which the vibration frequency is linearly dependent to the input voltage. In this way, the worst-case linear range of the output frequency of the proposed VFC is 0-55.40 MHz verified by simulations given a 0-0.9 V input range. The physical measurement of the proposed VFC shows a 0-52.95 MHz output frequency given a 0-0.9 V input range. The error in linearity is better than 8.5% while the power dissipation is merely 0.218 mW.     

隔离型DC/DC在高压电压电流源设计中的应用

由于隔离型DC/DC的安全性、隔离性等特征,该类器件广泛应用于多个电子、工业领域,本文主要介绍了隔离型DC/DC在高压电压电流源中的应用。本文将隔离型双输出DC/DC引入设计,利用DC/DC的隔离特性,将电压电流源的次级输出作为DC/DC器件参考地,将DC/DC器件的两路输出电压作为相关运算放大器的电源电压。常规高压电压电流源设计中需要大量采用高压运算放大器,采用此方案可使用较少的高压运算放大器及更低的成本实现相同功能,同时降低高压电源对PCB电路板上信号的影响。通过实际测量,文中方案输出稳定、精度高,满足设计与使用要求。文中用功能图纸对此类应用进行了详细说明。     

汇川技术HD92高压变频器在高炉鼓风机上的应用

本文介绍了汇川技术HD92系列大功率高性能高压变频器在钢铁行业高炉鼓风机上的成功应用,系统采用了双机并联方案,并且具备工变频的无扰切换功能,能够实现单台故障时,另一台不停机且能够无扰切换至工频运行。     

悬浮型高压窄脉冲放大器的研究

悬浮型高压窄脉冲放大器输出的是脉宽100ns、上升/下降沿10ns的高压脉冲,运用其中的DC/DC变换器处于动态悬浮隔离供电状态.为使DC/DC变换器适用于高压瞬态跃变状态,首先要求DC/DC变换器的输入/输出耦合电容的存在不影响高压窄脉冲的质量,其次是输出高压窄脉冲时的高速瞬态跃变不会影响DC/DC变换器的供电稳定性.因此,研究悬浮型高压窄脉冲放大器的驱动方式,就是要着重分析动态运用中的DC/DC变换器的工作状态.     

小型化直流电源发展动态

随着电子整机向小型化、轻量化方向的发展，对整机所用的直流稳压电源也提出了小型化的要求。本文叙述了国外ＤＣ／ＤＣ变换器的研究与开发情况，介绍了国内发展集成化直流稳压电源的现状，分析了国内市场对ＤＣ／ＤＣ变换器的需求。对国内外在该领域的技术水平进行了比较，提出了发展我国小型化直流电源的对策。     

Fabrication of 3D MEMS toroidal microinductor for high temperature application

Based on Microelectromechanical systems (MEMS) technique and thick photoresist lithography technology, a new toroidal-type inductor for high temperature application has been successfully developed. In the fabrication process, heat-resistant materials are used, alumina as insulator and supporting materials instead of polyimide, heat resistant glass for underlay instead of normal glass, and copper for coil. The maximum inductance is 87 nH at 0.826 GHz and maximum of quality factor (Q-factor) is 4.63 at 0.786 GHz, at room temperature. With simulation of thermal deformation, it shows that the developed toroidal inductor can be suitable for high temperature application, from 300 to 700 °C.     

Electrically Enhanced Readout System for a High‐Frequency CMOS‐MEMS Resonator

The design of a CMOS clamped‐clamped beam resonator along with a full custom integrated differential amplifier, monolithically fabricated with a commercial 0.35 μm CMOS technology, is presented. The implemented amplifier, which minimizes the negative effect of the parasitic capacitance, enhances the electrical MEMS characterization, obtaining a 48 × 10⁸ resonant frequency‐quality factor product (Q×f_res) in air conditions, which is quite competitive in comparison with existing CMOS‐MEMS resonators.     

CMOS MEMS技术的现状及展望

简要介绍了MEMS的发展状况及CMOS工艺在MEMS中的地位。主要介绍了pre-CMOS，intermediate-CMOS和post-CMOS三种不同的CMOS MEMS工艺。详细讨论了CMOS MEMS今后将面临的挑战及其未来应用领域，最后，根据国内情况对我国CMOS MEMS的发展提出了建议。     

一种用于升压型DC/DC变换器的低压带隙基准源

设计了一种应用于升压型DC/DC转换器芯片的高精度、低电压、低功耗带隙基准电压源,包含恒定电流的偏置电路、低压低功耗的运算放大器、三极管级联的带隙基准核心电路和低压启动电路四个部分。经过理论分析和仿真模拟,采用华虹NEC的5 V 0.35μm 1P4M工艺流片成功。电路实测结果为:输出电压Vout=1.2 V,温度系数12.5 ppm/℃,工作电压1.3~5 V,随电源电压的变化率为0.78 mV/V,3 V供电下功耗9μA。该带隙基准源可用于实际产品的批量生产。     

RF MEMS技术

通信收发机、天线等无线设备的发展趋势是高性能、小体积、低成本。微电子机械系统技术在这一趋势中显现了技术潜力。本文阐述了RFMEMS技术的现状。     

高稳定性Buck型DC/DC变换器设计

提出了一种基于模拟反馈的高稳定性Buck型DC/DC变换器的结构,使得电路在输入电压和负载变化时,具有输出电压稳定,波动范围和纹波小的特点.根据基于UMC 0.18μm工艺下的模型参数,使用Hspice对整个变换器进行仿真,给出了仿真结果表明电路设计的正确性.     

Evolution of a CMOS Based Lateral High Voltage Technology Concept

This work describes the evolution of a CMOS based lateral high voltage (HV) technology concept, where the HV part is integrated in a low voltage (LV) CMOS technology. The starting point is an existing substrate related state of the art 0.35 μm LV CMOS technology (C35) which is optimized for digital and analog applications. The technology covers two different gate oxide thicknesses which allow to control two LV logic levels with different gate voltages and drain voltages (max.V_GS=max.V_DS=3.3V, max.V_GS=max.V_DS=5.5 V). The key requirement for the HV integration is to preserve the LV design rules (DR) and the LV transistor parameters. Only in this case it is possible to reuse the digital and analog intellectual property (IP) blocks. The major challenge of this integration is to overcome the relatively high surface concentration of the 0.35 μm CMOS process which defines the threshold voltages and the short channel effects. Because the HV devices use the same channel formation like the LV devices, a process concept for the drift region connection to the channel is the key point in this integration approach. A benchmark for the process complexity is given by the mask count (low volume production) and the number of alignments (high volume production). Starting from a very simple approach n-channel HV transistors are described which can be integrated in the substrate related LV CMOS concept without adding additional masks. During the next steps the LV CMOS process is modified continuously using additional masks and alignment steps. From each step to step the new HV properties are explained and the trade-off between process complexity and device performance is discussed.     

一种55 V输出小功率DC/DC变换器的设计

介绍了一种小功率混合集成DC/DC变换器的设计思想、实现方法及测试结果。设计的电路采用光隔离单端反激式拓朴结构和混合集成工艺技术制作,输出电压为55 V,输出功率小于2W,工作温度为-55~105℃,体积为27 mm×27 mm×6.5 mm。该电路具有电压稳定、精度高、纹波小、调整率优良和可靠性高等特点,可应用于各类精密电子设备中。     

A new MEMS based variable capacitor with wide tunability,high linearity and low actuation voltage

We have proposed a new RF MEMS variable capacitor to achieve high linearity, wide tunability and low actuation voltage. The idea is based on increasing the linear region in the gap between the plates of the capacitor. It is done by adding a fixed-fixed beam below the fixed-free beam. The fixed-free beam is one plate of the capacitor. The voltage is applied to the fixed-free beam. In the vicinity of the pull-in voltage, the fixed-free beam losses its equivalent stiffness. The fixed-fixed beam is located in the vicinity of pull in situation of the fixed-free beam. This condition increases the equivalent stiffness of the fixed-free beam and allows the beam to continue moving down linearly and consequently increases the maximum capacitance of the structure. Geometrical and material property effects of the second beam on the linearity, tunability and voltage are investigated. The governing nonlinear equation for static deflection of the beam based on the Euler–Bernoulli beam theory has been presented.     

降压型DC/DC开关电源中的电压前馈技术

介绍了一种应用于降压型DC/DC开关电源的电压前馈技术,通过调整内部三角波的中心电压,使PWM信号占空比跟随输入电源电压快速改变。该技术能有效抑制输入电源电压变化对输出电压的影响,增强输出电压的稳定性。     

一种用于微拉伸系统的MEMS弹簧设计与制作

针对微拉伸测试系统支撑梁因塑性变形带来的误差,采用UV-LIGA技术制备出S型支撑弹簧来代替刚性梁,这样即可测量大变形薄膜的力学性能.实验结果表明,用UV-LIGA工艺制备的Ni金属S形弹簧具有良好的均匀性,在较大的变形范围内有很好的线弹性.     

DC/DC中子辐照试验在线测试技术研究

结合DC/DC变换器的工作原理,介绍了其中子失效模式以及试验环境,讨论了DC/DC变换器中子试验的在线测试技术,提出了解决长线造成测量误差的具体办法。在实际应用过程中,对变换器进行了电压校准,达到了在0~20 V范围内电压测试误差不超过±50 mV。     

Advanced power semiconductors and ICs for DC/DC converter applications

This paper describes recent advances in power semiconductor devices, integrated circuits, and packages for DC/DC converter applications. Special emphasis is placed on the latest discrete power MOSFET devices and packages. Features and trends in ICs for control of synchronous buck converters are highlighted as well. The paper will also cover a new class of miniaturized hybrid assembly that sets new efficiency standards for high current low output voltage applications.     

提高低电压DC－DC变换器效率的的同步整流技术

提出了一种新的同步整流方案，采用ＭＯＳＦＥＴ与肖特基二极管并联组合的方法构造同步整流结构，因而控制简单，工作稳定可靠。理论和实验结果表明，文中所述方法可显著提高低电压ＤＣ－ＤＣ变换器效率，适合于混合集成。     

Computational study of variations in gap size for the electrostatic levitating force of MEMS device using dual BEM

For MEMS combdrive performance, the calculation of levitating force due to electrostatic field is very important, and an accurate electrostatic analysis is essential. Because the gap size between combdrive fingers and ground plane or movable finger and fixed finger, plays a very important role for levitation, a study of the effect of gap size variation is indispensable. For diverse gaps of MEMS comdrive design, the dual BEM (DBEM) has become a better method than the domain-type FEM because DBEM can provide a complete solution in terms of boundary values only, with substantial saving in modeling effort, hence the DBEM was used to simulate the fringing of field around the edges of the fixed finger and movable finger of MEMS combdrive for diverse gap size. Results show that the less the gaps between combdrive fingers and ground plane are, the larger the levitating force acting on the movable finger is. In addition, the levitating force becomes more predominant as the gaps between movable finger and fixed finger decrease. By way of DBEM presented in this article, an accurate electrostatic field can be obtained, and the follow-up control method of levitation force for MEMS combdrive can be implemented more precisely.