Experiment No 01 - Lecture notes 3 PDF

Preview

Summary

nice...

Description

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Lab # 1 PSPICE: Introduction, DC Operating Point, DC Sweep, AC sweep, and Transient Analysis Objectives: After this lab, students will be able to understand the following features of PSPICE; 1. Use to capture component information system, CIS, to draw circuits. 2. Using the four point Analysis provided by the PSPICE 3. DC Bias Analysis 4. DC Sweep Analysis 5. AC Sweep Analysis 6. Transient Analysis

Components and Instruments:  

Components: No component required. Instruments: Computer with OrCAD PSPICE installed.

Literature: There are number of resources available for learning PSPICE on internet. However comprehensive introduction for PSPICE operation can be found at the following link:

http://www.seas.upenn.edu/~jan/spice/PSPICEPrimer.pdf

Introduction: Motivation: Before invention of PSPICE, the designed circuits were verified through breadboard and instruments like power supply, signal generator, oscilloscope etc. However, such verifications were not reliable either in terms of time or cost, as any wrong connection or design could be harmful.

COMSATS University Islamabad, Sahiwal Campus

Page 1

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

SPICE is abbreviated as Simulation Program with Integrated Circuit Emphasis that was developed at Electronics Research Laboratory of University of California, Barkeley. It is considered as a software-type breadboard, but much more powerful than the actual breadboard. The SPICE has virtual probes, measurements that speed up the verification. There are different commercialize SPICEs setup available in the market and are used in different orientations. The OrCAD PSPICE of Cadence is employed for regular simulation, whereas, the ICAP4 PsSpice of the IntuSoft for power applications, and the HSpice of synopsys for accurate simulations.

Setup Guide: A complete setup is available at the following link: http://www.orcad.com/resources/orcad-downloads After clicking the above link, a pop up window will be appeared. Proceed as per directions specified in figure 1.

Fig.1 Downloading OrCAD PCB Designer Lite

Fill in the required information; you will receive a link in your email. Click the link and select “OrCAD 16.6 Demo software (Capture and PSPICE only)” under “OrCAD Demo software” to download the installer. While installing the software three options should be selected;

COMSATS University Islamabad, Sahiwal Campus

Page 2

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

1. Capture CIS (for circuit drawing) 2. PSPICE (Circuit Simulation) 3. Use of Capture CIS: 4. Opening a new projects

To start the program, click on start and follow “All Programs”, “OrCad Family Release 9.2 Lite Edition”, and “Capture CIS Lite Edition”. To open a new project go to File menu and click on New Project as shown in figure 2 below;

Fig.2 creating new projects

COMSATS University Islamabad, Sahiwal Campus

Page 3

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Placing components (Electrical Components): After the step-1, a new project and a blank schematic are ready for drawing circuit. In order to place components, click the button at the right toolbar as shown in figure 3.

Fig.3 Placing Components

When using the software for the first time, there are no libraries already existed. All libraries are in “.obl” for its file extension and these are under the folder of “C:\Program Files\OrcadLite\Capture\Library\PSPICE”. Each library contains different components like shown in figure 4, select the specified libraries if anyone is sure about these.

COMSATS University Islamabad, Sahiwal Campus

Page 4

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Fig.4 Adding Libraries

COMSATS University Islamabad, Sahiwal Campus

Page 5

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Connecting components together: To connect components together, click the button as shown in figure 5 below and then click on the two points of the connection where a connection is required.

Fig.5 making connections using wires

Editing Components Properties: Normally there are two properties that we can edit “Part reference”: and “Value” as shown in figure 6. For example double click on R-1 can edit its “Part Reference”. This is required when the same “Part Reference” is occurred, and it is not accepting while compiling.

Figure 6: Editing components part reference and value parts

COMSATS University Islamabad, Sahiwal Campus

Page 6

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Circuit Analysis: Setting of ground part: While drawing circuit in Capture CIS, the ground should be set first, or else the compilation (net list generation) will generate an error massage. To set the ground component, double click on it and following windows will be displayed as shown in figure 7. Change the content name in “Name” column into “0”, close that window and thus complete the setting of ground component.

Figure 7: pop up window of ground component for editing the ground name to zero

Bias Point Analysis: Purpose of this analysis is to observe the voltage and current at steady state. Firstly, the designed circuit is drawn using “Capture CIS/Schematic window”. Before starting a simulation, click on the “New Simulation Profile” option to save the simulation by its name like bias as shown in figure 8. After the new simulation profile setting, click on “Edit simulation setting”, and choose “Bias Point” option in list and there is no other modification required as shown in figure 9 below.

COMSATS University Islamabad, Sahiwal Campus

Page 7

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Figure 8: New simulation profile setting for an analysis

Figure 9: Bias point analysis settings

COMSATS University Islamabad, Sahiwal Campus

Page 8

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Go to the PSPICE tab and select Run for DC bias point analysis. The simulation window will appear as shown in figure 10 below. When the simulation has completed, close this window and the schematic will reappear. When the V, I, and W tool buttons are activated, the results of the voltage, the current, and the power dissipated in that component will be shown. The tool buttons alongside the V, I, and W buttons allow you to alternately toggle a highlighted value OFF and ON.

Figure 10: simulating the circuit for bias point analysis

DC Sweep Analysis: The purpose of this analysis is to sweep input voltage and observe the output current. Here, we are going to observe the relationship between the voltage and current in Ohms’s law for the above circuit. Similar to the setting in “Bias point analysis”, we have to open a “New Simulation Profile” before the simulation. In simulation setting, we have to choose “DC point”. In the column of “Sweep variable”, it is needed to choose the sweeping source and type in its name as V1 shown in figure 11 below. In column of “sweep type”, “Linear” means the input voltage is swept in the form of 1, 3, 5….; while “Logarithmic” means the input voltage is swept in the form of 1, 10, 100.

COMSATS University Islamabad, Sahiwal Campus

Page 9

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Figure 11: DC sweep settings After running the simulation, we can observe that current is on Y-axis and voltage is on X-axis and they are in linear relationship shown in figure 12.

Figure 12: Relationship in between voltage and current in DC sweep

COMSATS University Islamabad, Sahiwal Campus

Page 10

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

AC Sweep Analysis: Purpose of this analysis is to sweep the input frequency and observe the output response. Here, we are going to observe the frequency response of an RC network. The transfer function of RC circuit is shown below;

V o (s ) 1 = V i (s) 1+ sCR

Similar to DC sweep analysis, here you will again do the new simulation profile setting under PSPICE tab, then in edit simulation profile option, select the AC sweep option in list, and provide the start, end frequencies and points/decade as shown in figure 13 below.

Figure 13: AC sweep analysis settings A pole frequency of an RC circuit is actually the cut-off frequency. The cut-off frequency of above RC circuit is 320 kHz and it is shown in figure 14 after simulating the circuit.

COMSATS University Islamabad, Sahiwal Campus

Page 11

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Figure 14: Frequency response of RC circuit and its pole frequency point along X-axis

Transient Analysis: The purpose of this analysis is to sweep the time variable and observe the time-variant voltage or current. In this part, we are going to compare the input and output voltages, where they are different in amplitude and phase. This phenomenon can be explained on the basis of simulation result in AC sweep analysis. Similar to previous settings, here we have to choose “Time Domain (Transient)” option as shown in figure 15. “Run to time” means what time do you want to stop the time sweeping. “Maximum step size” means the time sweeping accuracy, the smaller the step size, the simulation result is more accurate.

COMSATS University Islamabad, Sahiwal Campus

Page 12

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Figure 15: Time domain (transient analysis) setting Having insight into the RC network, various input frequencies are applied and circuit results are shown in below figure 16.

COMSATS University Islamabad, Sahiwal Campus

Page 13

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Figure 16: Transient analysis in AC cirucit

In-Lab Tasks: Task 01: Bias Point Analysis The purpose of this analysis is to observe the voltage and current at steady state. Follow the below given procedures for this analysis. 1. Connect the circuit as shown below and set the values as explained above. 2. Set the DC voltage source equal to 10V and resistor is set equal to 50 ohms. (The symbol for prefixes such as kilo and milli and mega are case insensitive can be confusing e.g. the symbol for kilo is K or k , for milli it is M or m and for mega it is MEG or meg). 3. Go to the PSPICE tab and then go to edit simulation profile, and then choose “Bias Point” in “Analysis Type”. 4. Go to the PSPICE tab and select Run. The simulation window will appear. 5. When the simulation has completed, close the simulation window and the schematic will reappear. 6. Activate V, I, and W tool buttons to obtain the values of the voltage, the current, and the power dissipated in circuit components. 7. Record the values for below variables COMSATS University Islamabad, Sahiwal Campus

Page 14

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Put data of task-01 here: Current via resister

I R 1=¿

Voltage across resistor

V R 1=¿

Power generated by source Pg =¿ Power dissipated by resister

Pd =¿

Figure 17: Circuit diagram for task 01

Task 02: DC Sweep: The purpose of this analysis is to sweep input voltage and observe the output current. Here, we are going to observe the relationship between the voltage and current in Ohms’ law for the above circuit. 1. Open a “New Simulation Profile” before starting the simulation and give name as DC sweep. 2. Go to the “Simulation setting” by clicking on edit simulation profile option under PSPICE tab and choose “DC Sweep” in “Analysis Type”. 3. In the column of “Sweep variable”, choose the sweeping source and type in its name as V1 if the source name is V1 otherwise give that name which you set for the source like V2, V3 or any else. 4. In column of “sweep type”, “Linear” means the input voltage is swept in the form of 1, 3, 5….; while “Logarithmic” means the input voltage is swept in the form of 1, 10, 100. 5. Go to the PSPICE tab and select Run. The simulation window will appear (Observe that voltage is along x-axis and current is along y-axis). 6. Plot the resulting relationship between voltage and current.

COMSATS University Islamabad, Sahiwal Campus

Page 15

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Plotting of DC sweep analysis: Plot the relationship between voltage and current. Also comment on the relationship.

Figure 18: Relationship between voltage and current in DC sweep analysis

Task 03: AC Sweep Analysis: Purpose of this analysis is to sweep input frequency and observe the output response. 1. Replace the 10 Vdc source with 1 Vac and place 50nF capacitor in series with 50 ohms resistor. 2. Go to the “Simulation setting” and choose “AC Sweep” in “Analysis Type”. 3. Select the logarithmic scale in AC sweep type and select the start frequency and end frequency range (say 10MHz as start and 100 MHz as end). 4. Find out the pole frequency using cut-off frequency formula for RC circuit as given as Fc =1/2 πRC

5. Go to the PSPICE tab and select Run. 6. Observe the pole frequency and match it to the value calculated in step 4. 7. Plot the magnitude characteristics (magnitude bode plot) of the given circuit and mark the pole frequency point

COMSATS University Islamabad, Sahiwal Campus

Page 16

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Plotting of AC sweep analysis:

Figure 19: Plotting of magnitude characteristics of RC circuit

Task 04: Transient analysis: The purpose of this analysis is to sweep the time variable and observe the time-variant voltage or current. In this part we are going to compare the input voltage and output voltage, where these are different in amplitude and phase. 1. Replace the 1 Vac source with sine source and set VOFF=0V, VAMP=3.3, and FREQ= 50KHz. 2. Go to the “Simulation setting” and choose “Transient Analysis” in “Analysis Type”. 3. Select “Run to time (means what time do you want to stop the time sweeping)” as 0.1msec and “Maximum step size (means the time sweeping accuracy)” as 10nsec.

4. Run the simulation for 300 KHz and 1000 KHz frequencies as well. 5. Record the voltage waveforms across capacitor and resistor in one plotting window (at three different frequencies) and show them below

COMSATS University Islamabad, Sahiwal Campus

Page 17

Lab#01: PSPICE: Introduction, DC operating point, DC sweep, AC sweep, and Transient analysis

Analysis/Conclusion:

Post-lab Work: Question 01: Write down the purpose of bias point analysis, DC sweep analysis, AC sweep analysis and Transient analysis? Question 02: Design the below circuit in PSPICE and then apply transient analysis to show the output voltage and current. Set the TCLOSE switch at three different times and then simulate the circuit at three different times (show output voltage and current at each time of TCLOSE).

COMSATS University Islamabad, Sahiwal Campus

Page 18...