Teaching mixed-signal integrated circuit design to undergraduates

A two-course sequence that teaches the basic concepts associated with digital, analog, and mixed-signal integrated circuit design for senior-level undergraduate students has been developed. The use of hands-on experiences using custom integrated circuits is employed to help teach these complex topics. This sequence has been taught for three years, and the affective learning has been assessed through precourse and postcourse surveys, focus groups, and in-class surveys.     

一种国产数模一体化控制电路的测试解决方案

以B61580芯片即国产数模一体化控制电路为例,介绍了一种适用于数模混合信号集成电路测试的新方法.在此基础上,通过引入和运用测试向量控制指令、利用Delphi开发环境设计了一个测试向量调整软件,并将该软件应用于测试调试过程中,从而高效地实现了该电路的测试调试和生产验证.     

Emerging SiGe HBT reliability issues for mixed-signal circuit applications

We review the emerging reliability issues associated with high-performance SiGe HBT technologies which are being increasingly deployed in a wide variety of mixed-signal circuit applications. For the purposes of this work, we define the concept of device "reliability" to be broader than its standard usage in the industry, to include all possible transistor degradation mechanisms, for all possible mixed-signal circuit designs, in any of the various intended mixed-signal applications. For instance, in addition to classical device reliability mechanisms associated with reverse emitter-base and high forward current density stress, new reliability issues for SiGe HBTs, including impact-ionization induced "mixed-mode" stress, scaling-induced breakdown voltage compression and operating point instabilities, geometrical scaling-induced low-frequency noise variations, and the impact of ionizing radiation on device and circuit reliability, are also addressed.     

A virtual classroom approach to teaching circuit analysis

We have implemented several innovative uses of computers and computer networks to develop a new pedagogy for the delivery of university engineering courses. These uses of computers and networks are creating efficiencies in the learning process, and students have found this interactive learning environment to be a significant improvement upon a traditional engineering course. Student performance and retention, as well as faculty productivity, are increased in this innovative teaching and learning environment     

A spice-based approach to steady state circuit analysis

A new SPICE-based approach for steady state circuit analysis is presented which uses SPICE computational capabilities and a master programme to carry out the periodic response. the master programme implements a suitable method for steady state analysis and is linked with SPICE only via I/O SPICE files. This allows the use of all SPICE analyses together with the new one simply by adding a new statement in the input SPICE file. In this paper the bases of this technique, including the chosen steady state method and the whole system structure, are discussed. Simulation results produced by this technique have been compared, by means of two meaningful examples, with those obtained both by SPICE and by a dedicated simulator for steady state analysis working in the frequency domain.     

A new approach to routing of two-layer printed circuit board

This paper presents a new method for routing two-layer printed circuit boards with fixed geometry, i.e. alternate columns of pins and vias. Circuit components are mounted on top of the board, and conductor wires are to be laid on the board such that circuit connections can be properly made. The proposed approach gives 100 per cent routability. The method consists of three steps, namely: partitioning of multi-pin nets into 2-pin subnets, via assignment, and routing on the two layers. In comparison with the traditional unidirectional routing, the method offers more flexibility and it requires usually about half as many vias. A computer program based on the presented algorithms was written. Its implementation is presented along with testing examples.     

A new public-domain program for mixed-signal simulation

A new public-domain simulator for mixed-signal circuits is described. The new simulator is very versatile, allowing the user to define new elements easily. The procedure adopted for simulation of circuits with both digital and analog elements is briefly discussed. Several simulation examples are presented to demonstrate the applications of the simulator. The simulator is expected to be particularly useful for engineering teachers in developing countries where access to expensive commercial mixed-signal simulators may be difficult     

A fundamental approach to transformer thermal modeling. I. Theoryand equivalent circuit

A simple equivalent circuit to represent the thermal heat flow equations for power transformers is presented. Key features are the use of a current source analogy to represent heat input due to losses, and a nonlinear resistor analogy to represent the effect of air or oil cooling convection currents. The effect was first quantified in 1817. It is shown that the idea of “exponential response” is not the best way to think of the dynamics of the situation. It is also shown that one can consider ambient temperature to be a variable input to the system, and that it is properly represented as an ideal voltage source     

IPM短路测试与短路能力分析

本文说明了IPM产品短路测试的基本方法,针对目前市场上常用的IPM产品进行短路测试并取得短路电流波形,分析了影响IPM产品短路能力的几个因素,结果发现,温度越高IPM产品的短路能力越差;驱动电源电压越大,短路耐量越差;IGBT的MOS沟道宽度越宽,IPM的短路能力越差。     

Nullator-norator approach to analogue circuit diagnosis using general-purpose analysis programmes

In this paper a decomposition approach to diagnosis and fault prediction in large analogue and switched capacitor circuits is proposed, reduced to an analysis of the corresponding nullator-norator models at a single test frequency. Algorithms for isolation of faulty nodes and subcircuits are presented. the topological conditions for performing diagnosis of faulty nodes and for identification of faulty elements have been considered. the element tolerance variations and measurement errors have been taken into account. the possibilities of the general-purpose programmes for frequency and worst-case analysis have been used in the practical implementation of diagnosis and fault prediction. Diagnosis of benchmark circuits has been performed and the results of a computer simulation using the programme PSpice are presented.     

静态电气短路试验方法

以新建大型机组调试工作为例,针对启动期间电气动态试验中短路试验存在的不足,提出采取静态电气短路试验方法.实践证明:该方法完全可行,且节省了资金,缩短了整套启动试验时间.     

A tabu search approach to generating test sheets for multiple assessment criteria

A computer skill certification test is one of the most important methods for evaluation of a student's computer ability. Since the tests are held frequently, one must efficiently and effectively compose test sheets from a large item bank containing over 10 000 test items. To certify student computer skills fairly, the composed test sheets must meet multiple assessment criteria such as the ratio of relevant concepts to be evaluated, the average discrimination degree, the difficulty degree, and the estimated testing time. One must allow significant time to compose an optimal test sheet from a large item bank by generating and testing each possible combination of test items. To cope with this problem, a Tabu search-based approach is proposed for more efficient composition of near-optimal test sheets from very large item banks, while meeting multiple assessment criteria. Based on the proposed approach, a computer-assisted testing system has been developed, and a series of experiments have been conducted to compare the efficiency and efficacy of this approach with other approaches. The experimental results show that the new approach is desirable for the composition of near-optimal test sheets from large item banks.     

Comparing test requirements for low-voltage circuit breakers

Low-voltage circuit protective devices include low-voltage power circuit breakers, insulated case circuit breakers, and molded case circuit breakers. Each of these circuit breaker types is used for particular applications, and is tested against standards that relate to those applications. In North America, low-voltage power circuit breakers are designed and tested in accordance with ANSI/UL standard 1066, which in turn refers to the series of applicable ANSI C37 standards. Insulated case circuit breakers and molded case circuit breakers are designed and tested in accordance with the UL standard 489. In this paper the standards are compared by means of tables. The standards for low-voltage power circuit breaker and the molded case circuit breaker have many common elements. As a consequence, either type of circuit breaker could be used for some applications. However, there are several significant performance differences that relate to the application of these circuit breakers. Specifically, the low-voltage power circuit breaker is normally applied upstream of the molded case circuit breakers     

Fundamental studies on vacuum circuit breaker arc quenching limitswith a synthetic test circuit

The aim of this work is to demonstrate the use of a synthetic test circuit with LC resonant circuits for fundamental experimental work on CB (vacuum circuit breakers). Studies have been performed on a 36 kV-model CB at test currents of 5 and 10 kA r.m.s. aimed at separating the influence of different parameters of the transient recovery voltage such as average rate of rise and peak value on the breaking capability. Furthermore, the effect of the arcing time on the measured arc quenching limit is presented     

A new neural networks approach to on-line fault section estimationusing information of protective relays and circuit breakers

This paper proposes a new neural network diagnostic system for online power system fault section estimation using information of relays and circuit breakers. This system has a similar profile of an expert system, but can be constructed much more easily from elemental samples. These samples associate fault section with its primary, local and/or remote protective relays and breakers. The diagnostic system can be applicable to the power system control center for single or multiple fault sections estimation, even in the cases of failure operation of relays and breakers, or error-existent data transmission. The proposed approach has been practically verified by testing on a model power system. The test results, although preliminary, suggest this system can be implemented by various electric utilities with relatively low customization effort     

一种通用测试工程建模平台的设计方法

随着测试系统从单一的专用系统向多功能的通用开放系统方向发展,测试软件通用性实现方法的研究受到了广泛的关注。研究设计一套高效的、易于理解的通用测试软件系统成为自动测试领域的迫切需要,为了实现此目的,将重点提出一种测试工程建模平台(test engineering model platform,TEP)的设计方案。此方案的提出能够大大降低在产品测试信息建模时对传统测试人员编程能力的要求,它将会是维修、测试机载产品过程中的重要工具。该平台将应用于四线制电阻阻值的测量实验,并得出相关的实验数据论证TEP建模平台的可靠性和有效性。     

电话电路自动测试系统的开发

随着电力系统电话用户的增多,仅仅依靠手工方式确定电话业务的好坏不能有效确保通信线路的畅通.为此,设计开发了一种电话电路自动测试系统,文章从工作原理、设计结构、运行环境等方面详细介绍了系统的开发情况.该系统的成功开发,有利于电力企业提高设备运行效率,提升企业管理水平.