某片式塑封电感器的结构分析

从一例电感器的失效分析入手,对该电感器进行了结构分析,发现了电感器在结构设计上的几个缺陷,并对缺陷进行了分析。给出了改进建议。     

MnZn1000磁性材料在立式工字型固定电感器中的应用

通过分析和试验，给出了在立式工字型固定电感器中使用MnZn1000磁性材料，以改善立式工字型固定电感器的直流叠加特性的试验结果。该结果证明，本方法还可以大大降低工字型固定电感器生产成本，对生产其它电感器也具有指导意义。     

片式电感器筛选方法

概述了电感器的发展历程,重点介绍模压片式电感器、叠层片式电感器的结构特点,以及工艺条件对固有可靠性的影响,并对以上两种类型电感器主要失效模式及其失效机理进行了简要分析,针对电感器三种主要失效模式:电性能参数退化、开路、短路,设计了模压片式和叠层片式电感器的筛选方案,并取得一定效果.     

DC／DC电源用扁平式变压器的最新发展现状

ＤＣ／ＤＣ电源用扁平式变压器是近６０年来变压器技术领域中的第一次技术创新。它克服了传统变压器散热差、漏感大、高频特性差、制造工艺冗长以及体积大等一些缺陷。本通过讨论普通变压器存在的问题，进而介绍Ｆｌａｔ Ｔｒａｎｓｆｏｒｍｅｒ Ｔｅｃｈｎｏｌｏｇｙ公司在其变压压 和电感器中采用的一种独特的磁心配置结构，能在优化磁性元件性能的同时，缩小元件的外形尺寸。     

电感器磁芯材料特性的参数分析法

给出EMI电源滤波器用电感器的高频等放电路模型，并提出了一种获得磁芯材料性的参数分析方法，通过测量磁性磁芯电感器的插入损耗，进而得出材料的有效磁导率。对典型的罐形磁芯电感器进行测试，分析与计算，得出了有效磁导率随频率变化曲线，并分析了误差产生的原因。     

电感器的发展现状及趋势

我们通常所说的电感器是指广义的电感器件如变压器、线圈、扼流圈、磁珠,以及与电感器相关的复合元件。电感器的主要功能是筛选信号,过滤噪声,稳定电流及控制电磁波干扰。电感器可分为插装电感器、片式电感器两大类。片式电感器又可分为叠成片式电感器、绕线片式电感器、编织型片式电感器和薄膜片式电感四大类。其中叠成片式电感器和绕线片式电感器是最常用的两大类片式电感器。     

平面圆形螺旋电感器和变压器的计算机辅助设计

本文在准静态条件下,分析了应用于微波单片集成电路中的圆形螺旋电感器和变压器,举出了它们的等效电路.求得格林函数后利用矩量法求出了圆形微带线上的电流和电荷分布.导出了计算平面圆形螺旋电感器和变压器等电路中各元件数值的公式以及“S”参数表示式.编制了相应的程序.利用这些程序可以分析计算具有任意匝数(包括非整数)和各种几何参数的平面圆形螺旋电感器和变压器.平面圆形螺旋电感器的计算值与实验值比较,最大误差约为5%.     

引出结构对叠层片式电感器可靠性影响的研究

叠层片式电感器(MLCI)其引出结构在热应力冲击下,可能会形成开路,降低了MLCI的可靠性,进而影响到电子线路的整体功能。针对实际应用过程中一例叠层片式电感器(型号CH1608H22N)的失效,采用X射线检查、金相检查等分析方法对电感器的失效机理进行了分析。结果表明引出电极与内电极结合部位的热致失效导致了开路,进而研究了引出结构对MLCI可靠性的影响,设计出了一种新的圆弧型引出结构,通过实验验证该结构的耐流特性比直角型引出结构的提高了50%,产品可靠性得以改善。     

电子变压器和电感器的国际标准及采用情况分析

简述了电子变压器和电感器的IEC国际标准状况，讨论分析了国家标准、电子行业标准采用IEC国际标准的情况。     

电感器磁芯材料特性的参数分析法

文章给出EMI电源滤波器用电感器的高频等效电路模型,并提出一种获得磁芯材料特性的参数分析方法.通过测量磁性磁芯电感器的插入损耗,进而得出材料的有效磁导率.对典型的罐形磁芯电感器进行测试、分析与计算,得出了有效磁导率随频率变化曲线,并分析了误差产生的原因.     

Introduction to modeling of transformers and coupled inductors

A tutorial paper is presented on modeling and design of transformers and coupled inductors. Beginning with a brief review of electromagnetic laws and magnetic circuit models, the magnetic and electric models of transformers and coupled inductors are developed, including both magnetizing and leakage effects. It is shown that while the voltage waveforms on the windings are primarily related by the turns ratio for both devices, the winding currents of transformers and coupled inductors are determined by very different mechanisms. An integrated structure with both transformer and coupled inductor on the same core is also discussed, as well as the special case of the coupled inductor used on a multiple-output transformer-isolated converter     

Failure mode analysis of MEMS suspended inductors under mechanical shock

Micro-electromechanical system (MEMS) suspended inductors have been widely studied in recent decades because of their excellent radio frequency performance. However, few studies have been performed on the failure analysis of MEMS suspended inductors under mechanical shock. In this study, the failure of MEMS suspended inductors with a planar spiral coil is investigated through analytical and experimental methods. We present a stress and deformation analysis to study the failure mode of the suspended inductors under shock. To verify the theoretical analysis, MEMS inductors are designed and fabricated, and shock tests are carried out. The shock tests show that the failure mode of the MEMS suspended inductors is a fracture that occurs at the ends of the inductor coil, and the test results agree with the theoretical analysis.     

Analysis of eddy-current losses over conductive substrates withapplications to monolithic inductors and transformers

In this paper, a closed-form integral representation for the eddy-current losses over a conductive substrate is presented. The results are applicable to monolithic inductors and transformers, especially when such structures are realized over an epitaxial CMOS substrate. The technique is verified against measured results from 100 MHz to 14 GHz for spiral inductors     

Microwave transformers, inductors and transmission linesimplemented in an Si/SiGe HBT process

Experimental results are presented on microwave inductors, transformers, and transmission lines fabricated in an Si/SiGe heterojunction-bipolar-transistor process with standard metallization and a thick polyimide dielectric. Microstrip transmission lines with characteristic impedances from 44 to 73 Ω, Q's from 10 to 14, and insertion losses from 0.11 to 0.16 dB/mm at 10 GHz are presented. Conventional planar inductors with inductances from 0.5 to 15 nH and with peak Q's up to 22 are presented. Lateral transformers with a maximum available gain of better than -5 dB and a measured coupling coefficient (k) of 0.6 at 5.5 GHz and 0.4 up to 12.5 GHz are also discussed     

Ferrites for linear applications II?Performance requirements

The final installment of this article focuses on the applications and performance requirements of soft ferrite materials. Basic devices employing ferrites include inductors for FDM filters, wide-band and pulse transformers, and high-frequency power transformers. In the typical modern television receiver a total of about 0.6 kg of ferrite cores is used in a variety of applications, such as line output transformers, deflection yokes, and convergence systems.     

30-100-GHz inductors and transformers for millimeter-wave (Bi)CMOS integrated circuits

Silicon planar and three-dimensional inductors and transformers were designed and characterized on-wafer up to 100 GHz. Self-resonance frequencies (SRFs) beyond 100 GHz were obtained, demonstrating for the first time that spiral structures are suitable for applications such as 60-GHz wireless local area network and 77-GHz automotive RADAR. Minimizing area over substrate is critical to achieving high SRF. A stacked transformer is reported with S/sub 21/ of -2.5 dB at 50 GHz, and which offers improved performance and less area (30 /spl mu/m/spl times/30 /spl mu/m) than planar transformers or microstrip couplers. A compact inductor model is described, along with a methodology for extracting model parameters from simulated or measured y-parameters. Millimeter-wave SiGe BiCMOS mixer and voltage-controlled-oscillator circuits employing spiral inductors are presented with better or comparable performance to previously reported transmission-line-based circuits.     

New active input current shapers to allow AC-to-DC converters withasymmetrically driven transformers to comply with the IEC-1000-3-2

Four new topologies of active input current shapers (AICSs) for converters with symmetrically driven transformers (such as half-bridge, full-bridge and push-pull) have been proposed. This paper analyzes the extension of the use of these new AICSs topologies to converters with asymmetrically driven transformers. Using some of these topologies, the size of AICS inductors can be reduced and even integrated in a single magnetic core. As in the case of other converters with AICS circuit, the new topologies allow line current harmonics to be reduced and thereby to comply with the IEC 1000-3-2 specifications, whilst maintaining all the features of standard DC-to-DC converters (e.g., fast transient response). Finally, the proposed topologies have been experimentally tested     

Turn-Coupling in Thick-Film Integrated Magnetic Components for Power Converters

Thick-film technology constitutes an alternative to develop low-power integrated magnetic components. This paper explores into the possibilities presented by such technology and proposes new conductor arrangements that allow turn-coupling to be obtained in thick-film magnetic structures. The benefit of having such a coupling is twofold. On the one hand, it allows inductors to be integrated in even smaller volumes. On the other hand, it makes it possible to design flat power transformers using this integration technique. A complete design procedure of both, power inductors with turn-coupling and power transformers, is presented in this paper. A full characterization of these thick-film transformers is also given. Some experimental results are included as well so that the reader can validate the modeling proposed.      

On-chip embedded toroidal solenoid inductors and transformers formed by post-CMOS micromachining techniques

This paper presents a micromachined implementation of embedded toroidal solenoids for high-performance on-chip inductors and transformers, which is highly demanded in radio-frequency integrated circuits (RFICs). Microfabricated on CMOS compatible silicon wafers with post-CMOS micromachining techniques, the RF toroidal components can constrain the magnetic flux into a well-defined path and away from other on-chip RF devices, thereby, being in favor of decrease in RF loss, increase in Q-factor and elimination of electromagnetic interference. By using a technical combination of an anisotropic wet etch and an isotropic dry etc., the micromachined toroidal structure can be used for the formation of metal solenoid by copper electroplating. Processed under low temperature (Max 120 °C for photoresist hard-baking), the three mask microfabrication can be compatible with CMOS IC fabrication in a post-process way. The formed toroidal inductors with 4.92 nH and 8.48 nH inductance are tested, and we obtain maximum Q-factors of 25.7 and 17.8 at 3.6 GHz and 3.1 GHz, while the self-resonant frequencies are 17.3 GHz and 7.4 GHz, respectively. On the other hand, two types of toroidal transformers are also formed and tested, resulting in satisfactory RF-performance. Therefore, the novel techniques for close-loop solenoid inductors are promising for high-performance RF ICs.     

Analysis, design, and optimization of spiral inductors andtransformers for Si RF ICs

Silicon integrated circuit spiral inductors and transformers are analyzed using electromagnetic analysis. With appropriate approximations, the calculations are reduced to electrostatic and magnetostatic calculations. The important effects of substrate loss are included in the analysis. Classic circuit analysis and network analysis techniques are used to derive two-port parameters from the circuits. From two-port measurements, low-order, frequency-independent lumped circuits are used to model the physical behavior over a broad-frequency range. The analysis is applied to traditional square and polygon inductors and transformer structures as well as to multilayer metal structures and coupled inductors. A custom computer-aided-design tool called ASITIC is described, which is used for the analysis, design, and optimization of these structures. Measurements taken over a frequency range from 100 MHz to 5 GHz show good agreement with theory