背靠封装混合电路的热分析

在大功率混合电路领域热学问题是一个关键问题,在典型的混合电路中由于热传导造成的传热是其主要传热方式,热分析应在设计阶段尽早完成,初祥完成后应进行实验验证。本文提出了用红外热象仪测量背靠封装的混合电路渡分布的实验结论并描述了如何计算它的结温升。测量结果证实用热散布角模型估算的结温升与实测值很一致以及引脚在散热中起重要的作用。     

采用最小封装尺寸实现业界最佳的转换器保护功能

飞兆半导体公司（Fairchild Semiconductor）为电源设计人员提供临界导通模式（Boundary-conduction Mode,BCM）交错式功率因数校正（PFC）控制器,可为AC—DC电源提供超过96％的功率转换效率。新产品适合的应用包括用于数字电视、台式电脑和入门级服务器、前端电信系统,以及额定功率范围从100～1000W的工业电源系统之电源。过往,具有高效率和低成本的BCMPFC转换器局限于约300W的最大功率水平。     

混合封装电力电子集成模块内功率电路对驱动保护电路的热影响

混合封装电力电子集成模块(IPEM)是目前中功率范围内电力电子集成的主要方式。IGBT器件与控制和驱动电路高密度地封装在一起,IGBT的发热对驱动保护电路会产生非常不利的影响,我们针对这个问题进行了研究。利用三维有限元法建立了模块内的传热模型,对不同发热功率下IGBT的结温以及驱动保护电路PCB的最高温度进行了计算和分析。另外,对功率电路与驱动保护电路PCB之间存在空气隙以及模块完全被密封后模块内的传热问题也进行了实验研究。     

封装高速电路

随着VLSI工艺的成熟和IC开始接近ECL电路的工作速度,封装工程师面临的任务是研究符合密度和固有时间延迟这两个规范的互连方法。一些试验性的VLSI芯片已经达到每片数十万门的集成密度。封装功能的指数增加要求有更多的输入/输出端。     

微波混合电路铝合金封装外壳电镀锡铋技术

混合集成电路中，封装一般采用表面电镀镍金可伐外壳。但是可伐表面镀金在实用中也有其固有的缺点，表面镀金层与电路焊接时，镀层金与焊料中的锡，电位差较大，存在原电池腐蚀的不利因素。铝合金上采用无铅锡铋镀层是一种较好的替代方案。本文采用盐雾试验法，对铝合金表面化学镀镍做底层及电镀光亮锡铋层做表层的样品进行抗腐蚀性研究，结果表明采用化学镀镍14微米和光亮锡铋7微米组合镀层的具有良好的抗腐蚀效果，可以承受72小时的盐雾试验。此外采用扫描电镜、X射线能谱仪对锡铋光亮镀层的成分进行分析，结果表明铋含量为1％，锡含量为99％。     

数模混合电路的全芯片防静电保护

随着集成电路的迅速发展,特别是数模混合电路的广泛应用,静电放电(ESD)已成为导致集成电路内部静电损伤的可靠性问题,它常常在集成电路的输入、输出端口以及从电源到地的电路内部形成,给芯片的制造和设计带来了很大的困难.文章对芯片防静电保护电路进行了总结,分析和讨论了几种数模混合电路防静电保护技术.     

最佳通用逻辑门及ECL电路实现

本文用ECL电路实现了文献[1]提出的最佳通用逻辑门ULG.2,并把它与传统的逻辑门进行了比较,认为这种U_2~(L)ECL电路,可以作为超高速中规模集成电路标准单元.     

利用PSPICE实现数字模拟电路的混合模拟

ＰＳＰＩＣＥ是一种能够数字模拟电路的混合模拟电子线路ＣＡＤ软件，文中讲述了ＰＳＰＩＣＥ的描述语言，使用方法，模型与参数，并讨论了ＰＳＰＩＣＥ的优势与不足。     

数字显示电路的设计与多芯片组件封装实现

由于MCM自身的特点，物理设计已成其瓶颈问题。本文在已有方案的基础上，设计实现了一个数字显示电路，并计算了各单元电路的相关参数，最后对电路进行多芯片组件(MCM)封装。仿真结果表明，该电路的最大电容量和响应时间等参数均能满足电路设计的要求。     

Impact Testing of Plug-In Circuit Packages for High Reliability

A mechanical impact test has been used to improve the production reliability of plugin circuit packages for a Bell System electronic switching system. Mechanically unstable components which could cause intermittent electrical failures in system operation are located by monitoring the electrical output of the package during the test.     

Feasibility Study of a Hybrid Mechanical-Static DC Circuit Breaker for Superconducting Magnet Protection

This paper describes the feasibility studies of a hybrid DC circuit breaker (CB) for quench protection of superconducting magnets rated for current up to some tens of kiloamperes (kA) and voltage of several kilovolts (kV). The proposed scheme is based on a mechanical switch paralleled to a fully controlled static CB; integrated gate commutated thyristors (IGCTs) were selected. In normal operation, the mechanical switch handles the continuous flow of DC current minimizing the on-state losses. When protection against quench is requested, the current is diverted into the static breaker that quickly interrupts the current, withstanding the reapplied voltage of several kV. The reliable turn-ON of several IGCTs in parallel with low voltage applied between anode and cathode is an issue to be assessed to confirm the feasibility of this design solution. The paper highlights that the components commonly used as snubber or protection circuit can guarantee the turn-ON of all the devices in parallel and that the IGCTs can be turned-ON with few volts applied; this latter aspect was proved by means of specific tests. Finally, a comparison between a static only and a hybrid CB is performed, highlighting the benefits introduced by the hybrid solution.     

Parallel Push-Pull Hybrid Circuit

This paper deals with a new hybrid circuit for signal branching or combining in parallel push-pull amplifiers. The purpose of the new hybrid circuit is to perform the branching or combining of two pairs of signals for parallel push-pull operation, each consisting of two oppositely phased, balanced signals. The advantage of combining two pairs of parallel push-pull signals by a single component of new hybrid circuit is clear; one would require a multiplicity of conventional rat-race circuits to do the same job, inasmuch as the basic rat-race circuit is limited to only one pair of push-pull signals. The new hybrid circuit is further elaborated to improve the performance for combining unbalanced push-pull signals by: (1) showing that the combination of unbalanced push-pull signals is equivalent to the super-position of cophase components on the balanced antiphase components; (2) analyzing the effect of the cophase components in the hybrid circuit; and (3) devising means of improving the adverse effects of the cophase components. Finally, an evaluation is made of a parallel push-pull amplifier using the new hybrid circuit in comparison with the conventional rat-race circuits required for the same parallel push-pull operation.     

USB3.0电路保护

USB3.0接口设备集合了通信速度为5Gbps的四个额外的数据通道,而且电源总线也有着高达900mA的最大输出电流。这些新的USB3.0规格加上集成芯片几何尺寸的不断缩小,使得预防电气瞬变和过流故障也变得更重要复杂。即使是很小的静电放电(ESD)和短路事故带来的危害也相比更大。寄生电容,低钳位电压和低电阻成为电路保护元件选择中的关键指标。本文网络版地址:http://www.eepw.com.cn/article/145483.htm     

高分子材料的电路保护器件和保险丝

Littelfuse及产品概况Littelfuse针对微电子电路和强电电路的保护,主要提供七种保护产品,在电信、便携式产品、家用电器、强电源方面都有一整套解决方案。在高分子材料产品方面,主要提供针对ESD(静电放电)的保护,以及针对过流或者短路方面的保护,比如PGB静电放电抑制器、PPTC(Polymer Positive Temperature Coefficient)可复用式保险丝。PGB主要用于接口部分的保护,PTC主要是串联在电     

一种新型过温保护电路

采用CSMC 0.5 μm工艺,设计了一种新型过温保护电路.从检测温度和控制温度两方面考虑,通过优化电路结构,提出一种新型系统解决方案.在不引入热振荡的前提下,实现稳定电路温度和输出关断信号的双重功能.采用Cadence的Spectre仿真器进行仿真,结果表明,温度在-50～200℃时,PTAT电压以10.5 mV/℃变化,过温保护开启温度为105℃,具有滞迟功能.成功流片后对芯片进行测试,结果显示,在20～130 ℃内,PTAT电压灵敏度约为10 mV/℃,过温保护开启温度的实测值与仿真值的偏差小于3℃,滞迟范围为20℃.该保护电路是开关电源IP的重要组成部分,在设计过程中时刻考虑其工艺健壮性和可重用性的约束条件,确保其可移植性.     

Analytical Evaluation of Via-Plate Capacitance for Multilayer Printed Circuit Boards and Packages

The via-plate capacitance for a via transition to a multilayer printed circuit board is evaluated analytically in terms of higher order parallel-plate modes. The Green's function in a bounded coaxial cavity for a concentric magnetic ring current is first derived by introducing reflection coefficients for cylindrical waves at the inner and outer cavity walls. These walls can be perfect electric conductor (PEC)/perfect magnetic conductor (PMC) or a nonreflective perfectly matched layer. By further assuming a magnetic frill current on the via-hole in the metal plate, an analytical formula is derived for the via barrel-plate capacitance by summing the higher order modes in the bounded coaxial cavity. The convergence of the formula with the number of modes, as well as with the radius of the outer PEC/PMC wall is discussed. The analytical formula is validated by both quasi-static numerical methods and measurements. Furthermore, the formula allows the investigation of the frequency dependence of the via-plate capacitance, which is not possible with quasi-static methods.      

IGBT短路保护的驱动电路的设计

IGBT（绝缘栅双极型晶体管）在现代电力电子技术中得到越来越广泛的应用。文中主要对绝缘栅双极型晶体管的驱动和短路保护电路进行了研究。首先谈论了IGBT的驱动电路的基本要求和短路保护分析,然后运用IGBT集电极退饱和原理,提供了一个采用分立元件构成的IGBT具有短路保护功能的驱动电路。理论分析和实验结果证明了所设计驱动电路的可行性,而且该电路简单实用,可靠性高。     

汽车网络的电路保护

新的汽车设计大量地依赖于电子电路来降低成本,改进可靠性和增加性能。汽车上增加的电气和电子系统使得电路保护成为关键的设计问题。无源元件的新汽车电子协会标准和IDB-1394多媒体网络要求正在提出用可再设置的聚合物正温度系数(PPTC)器件技术,来帮助保护汽车网络和电子元件因短路和过载引起的损坏。生活类信息和娱乐设计进入汽车汽车业正在开发开放网络标准以降低成本、保持不过时,以及加快上市时间。用在消费类信息和娱乐系统中的技术比汽车设计周期超前5~7年,移动娱乐类产品正在汽车和汽车零件市场迅速增长。一个通用总线可帮助汽车…     

一种用于马达驱动芯片的新型过温保护电路

为简化电路结构,提高精度和降低功耗,提出了一种新型过温保护电路。该电路无需基准电压和比较器,利用PTAT电流源的正温度系数特性,对温度进行检测,同时设计迟滞回路,避免了热震荡的发生。基于HHNEC的0.35μm BCD工艺实现,在电源电压为3V~5.5V下进行测试结果表明,该电路热关断温度为165℃,温度迟滞量为15℃,误差为1℃,与仿真结果一致,可以广泛应用于功率集成芯片中。