Table of Contents Assignment: 2 1 Introduction 1 1) You need to select an Op Amp circuit of your choice (inverting, non-inverting, summing, comparator, feedback, voltage regulator, etc.). Simulate the circuit in any of the packages you have identified in the first assignment, and then assess the performance of the software package by carrying out mathematical analysis of the circuit. 2 Op Amp Summing Amplifier 2 Op Amp Summing Amplifier Simulation 1 2 Op Amp Summing Amplifier Simulation 2 3 Results Simulation 1 & 2 5 2) Describe the following terms used in ECAD systems: 6 (a) Prototype 6 (b) Boundary scan 6 (c) Self-testing 7 (d) Controllability and observability 7 (e) Testability 7 (f) Simulation modelling 7 (g) Fault simulation 8 (h) Temperature simulation 8 3) VLSI 9 Conclusion 10 References 10 Online sources 10 Books 11
Assignment: 2
You are working for an electronic design services company. The company designs and engineers printed circuit boards. It specializes in interconnection design, and provides electronic design automation solutions.
As part of your training programme, your line manager has asked you to carry out the following task and to submit your findings in a report (around 6 pages).
Introduction
There is a huge prevalence in electronics in everyday products, there for R&D is a very important factor. Electronic Computer-Aided Design (ECAD) software are used to optimise existing products or to develop new concepts, giving the opportunity to realise virtual simulation that otherwise will be complicated to realise and will required a lot more time.
The aim of this research is to understand the features of ECAD systems and be able to apply it to design problems, be able to evaluate software package and the use of an ECAD system to contrast the results with mathematical calculations.
1) You need to select an Op Amp circuit of your choice (inverting, non-inverting, summing, comparator, feedback, voltage regulator, etc.). Simulate the circuit in any of the packages you have identified in the first assignment, and then assess the performance of the software package by carrying out mathematical analysis of the circuit.
Op Amp Summing Amplifier
For this simulation an Op amp summing amplifier has been used, this kind of amplifier has a virtual earth point, which allows the use of different number of voltages (d.c. or a.c.). This characteristic makes them suitable for diverse use such as “mixer” in audio systems to combine the output of microphones, electrical guitars, etc. Op amp summing amplifier is also used to perform mathematical calculations in analogue computing.
Op Amp Summing Amplifier Simulation 1
An Op amp summing amplifier circuit with 2 input voltage v1:2mVand v2:1mV in a.c. applied via R1/R7 with 10kOhms resistance and R2/R8 with 10kOhms resistance and 2 voltage sources v3 & v4 with 15 volts d.c. simulation 1 and 2 (fig: 1.1 & 1.3).
In Simulation 1 (fig: 1.1) the value for the feedback resistance ( Rf ) is 10kOhms whereas the In Simulation 2 (fig: 1.3) the value for the feedback resistance ( R11 ) is 20kOhms.
Using the formulas vout=-Rf(v1R1+v2R2) the 2 inputs voltages (v3 & v4) are added and amplified if Rf/R11 is greater each of the input resistors there is a voltage gain. With the use of the previous formula, it has been possible to contrast the results from Orcad simulation (fig: 1.2 & 1.4) to the mathematical calculation for a Summit Amplifier, in which the results has been the same.
As it can be seen in both mathematical calculation and Orcad simulation there is a gain difference in vout from circuit Op Amp Summing Amplifier 1 (fig: 1.1) which uses a 10kOhms resistance and circuit Op Amp Summing Amplifier 2 (fig: 1.2) which uses a 20kOhms resistance. The vout gain is proportional to the increase in feedback resistance going from –3mV using a 10kOhms resistance, to -6mV for a 20kOhms resistance.
Another differential characteristic that can be seen contrasting both simulations (fig: 1.2 & 1.4) is from the fact that in circuit Op Amp Summing Amplifier 1 (fig: 1.1) both v1:2mV and v2:1mV have a 1kHertz frequency whereas in circuit Op Amp Summing Amplifier 2 (fig: 1.3) v1:2mV has a 1kHertz frequency and v2:1mV has a 5kHertz frequency. As a result of applying 2 different frequencies vout wave in simulation 2 (fig: 1.4) has a characteristic wave form showing the combination of 2 sinusoidal wave with different frequencies in 1 wave form. 2) Describe the following terms used in ECAD systems: (a) Prototype
Prototype stands for the creation of a hardware part during the design process in order to realizes test and locate possible faults in the systems.
Fig:2.1. Evolution of design process
(Thermal analysis by Solidworks Simulation)
Software simulation in the design of electronic systems has reduced and even sometimes erases the need of a hardware prototype as can be seen in fig: 2.1.
(b) Boundary scan
Fig: 2.2. Boundary-Scan
(http://www.altera.com/support/devices/tools/boundary-scan/tls-boundary-scan.html)
Boundary-Scan (BST) allows the possibility of testing components on a Printed Circuit Board, Input and Output while the systems are functioning under standard circumstances allowing capturing functional data. This kind of testing does not require physical test probes, it is also capable of transmitting and receiving test signals from different integrated circuits integrated in a more complex system (fig: 2.2).
BST is a board-level testing tool which gives the possibility to find faults in the system, either being in component or connections in real time while the system is working.
(c) Self-testing
Built-in self test (BIST) stands for a system which is able to detect its internals faults without any other intervention.
(d) Controllability and observability
Controllability is considered the ability apply input patterns to set and clear internal signals; it is particularly useful to be able to change the state in registers inside a circuit.
Observability is considered as the capability to detect the reaction of a fault on an internal node via the primary outputs of a circuit.
(e) Testability
It has been a change from the way test and design are carry out, to the way it was done years ago, where design engineers and test engineers worked separately.
Nowadays, Design For Testability (DFT) considers the ways a system will be tested since the moment it is being designed rather than keeping the test up to the end of the design phase.
This methodology of design is organised in 3 levels: components, module and online built in self-test (BIST), as a result there is a reduction in labour needs, smaller and expectable development for bigger designs, increase of quality assurance and better maintainability for the end product.
(f) Simulation modelling
Simulation Modelling is a cost effective technique for estimating the performance and alternative working strategies.
A simulation model requires the following steeps, collection of data, analysis of data, and use of the analysis of the data in the simulation model. The data can be obtained from real time data of from historical records.
(g) Fault simulation
Fault simulation analysis of the behaviour of a system considers the possibility that a fault occur in the system applying different test to find out if there is a fault or not. The technique considers possible faults during manufacture, compute the results on the circuit output tacking into consideration that a fault is produce and that a fault is not produce. Each test is designed to show if there is a fault, if there is not a fault it is considered to be fault free.
(h) Temperature simulation
Overheating is a common fault of electronic devices, therefore the need for designing methods to cool down the system and prevent error in the system such as deformation or crack under thermal stress. Anything powered by electricity should be analysed for thermal performance in order to evade temperature problems.
In product-design thermal analysis software is used during the design process to evaluate heat flow by conduction, convection and radiation. The mentioned software has to take into consideration the result of the use of thermal resistance layer, time dependent such as heating or cooling, properties of material in different, temperatures, heat power, convection coefficients, and other boundary conditions.
Fig: 2.3. Temperature of the micro chip fluctuates as power is cycled on and off. Because of thermal inertia, the value exceeds the maximum allowed, 1200 °C.
(Thermal analysis by Solidworks Simulation)
A transient thermal analysis is needed to investigate the array temperature variation in the system being able to control the heat power using a thermostat. After defining the material properties, convection constants, preliminary temperature, and heat power, the test works for 300 seconds (Fluctuation in microchip temperature fig: 2.3)
3) VLSI
Fig: 2.3. Evolution of VLSi
(http://www.eolss.net/Sample-Chapters/C05/E6-195-04.pdf)
Very Large Scale Integration (VLSI) is the description for the process of conceiving, designing and fabrication for integrated circuits. As per the tendency of increasing the number of transistor reaching thousand and even millions of them, while reducing the size for the chips, the VLSI was applied. Nowadays chips the size of the chips has been reduce drastically and can contain billions of transistors. As shown in fig: the increase of transistor in the VLSI has seen a radical increase in the last decade.
VLSI is not just related to the number of transistors anymore, but to the complexity a chip has. VLSI includes a large number of digital and non-digital devices giving a high flexibility in to suite the need of the market. Therefore the updated definition VLSI is an integration of dense and complex chips system, which can be built on the same semiconductor or combining different ones connected by wires.
Conclusion
Electronics is a fascinating area under constant development, there is always the need for improvement in performance, reduction of size and if it is possible reduction in cost without losing performance. This report gives the opportunity to approach the one of the more powerful ECAD in the market and also the contents and history of very important component in electronics such as IC and PCB, VLSI and Amplifiers.
References
Online sources
Dassault Systemes. 2010. Solid Works Corporation. Thermal Analysis. [Online Source] Available online at: http://www.solidworks.com/sw/docs/thermal_2010_ENG_FINAL.pdf
Simon Moore. 2011. Computer design. University of Cambridge. Computer Laboratory. [Online Source] Available at: https://www.cl.cam.ac.uk/teaching/1112/CompDesign/ComputerDesignHandouts2011.pdf
Oriol F. Antonio P. Nikolaos B. 2012. MATLAB as a Design and Verification tool for the Hardware prototyping of Wireless Communication Systems. INTECH. [Online Source] Available at: http://upcommons.upc.edu/eprints/bitstream/2117/17773/1/InTech-Matlab_as_a_design_and_verification_tool_for_the_hardware_prototyping_of_wireless_communication_systems.pdf
R.G. Bennetts. 2002. Boundary Scan tutorial. [Online Source] Available at: http://people.ee.duke.edu/~krish/teaching/ECE269/boundaryscan_tutorial.pdf
Delia U; Francis S; Dominic K; Sorin M. 2005. Electronics: Simulation Modeling. Input Data Collection and Analysis. Bulgaria. University of Brasov. [Online Source] Available at: http://ecad.tu-sofia.bg/et/2005/pdf/Paper051-D_Ungureanu2.pdf
Altera Corporation. Altera Measure Advantage: Boundary-Scan Tool. http://www.altera.com/support/devices/tools/boundary-scan/tls-boundary-scan.html
Gloria Huertas; Emilio Lora. Circuits and Systems: Very-Large Scale Integration of Electronic Circuits. Encyclopedia of Life Support Systems. [online Source] Available at:http://www.eolss.net/Sample-Chapters/C05/E6-195-04.pdf
Books
S.L. Hurst. 1998. VLSI Testing: Digital and Mixed Analogue/Digital Techniques December. 1st edition. Publisher: The Institution of Engineering and Technology.
Amar Mukherjee. 1986. Department of Computer Science University of Central Florida: Introduction to nMOS and CMOS VLSI System Design. Published by Prentice Hall.
John Bird, 2010. Electrical and Electronic Principles and Technology. 4th edition. New York. Published by Routledge Taylor & Francis Group.
John Santiago.2013. Circuit Analysis for Dummies. New Jersey. Published by John Wiley & Sons.
John O’Malley. 2011. Basic Circuit Analysis. 2nd edition. USA. Published by Mc Graw Hill.
Robert L. Boylestad. 2014. Introduction Circuit Analysis. 1st edition. Published by Pearson Education Limited.UK.
