TINA-TI Simulation Software. Application Note

Transcription

1 TINA-TI Simulation Software Application Note Phil Jaworski Design Team 6 11/16/2012

2 Abstract TINA-TI is a circuit design and simulation tool created by both Texas Instruments and DesignSoft that has helped me and my design team create our final product; an ECG board for Texas Instruments. We have simulated every part of our board using this software and it has helped shape the exact design we eventually implemented. We started using it in our preliminary assignments of testing resistive and capacitive loads on printed circuit boards with Texas Instruments operational amplifiers, and eventually, in our entire circuit structure. Using the software is a very simple, yet accurate method of predicting the output response of both trivial and complex circuits. With its simplicity and quickness, we were able to test multiple possible designs in order to seek out the optimal layout for our ECG board. The effectiveness and ease of use of the software makes it of value to anyone who needs to build and test a circuit design. This application note will give the details of TINA-TI as well as give a tutorial to anyone interested in its use. Introduction TINA-TI is a powerful circuit design and simulation tool created by Texas Instruments and DesignSoft. It is ideal for designing, testing, and troubleshooting a variety of basic and advanced circuits, even complex architectures, without any device limitations. Texas Instruments and DesignSoft initially wanted to provide their customers and with a powerful circuit simulation tool that is equipped for simulating analog and switched-mode power supply circuits, but it is now available for the public. It is ideal for helping designers and engineers in developing and testing circuit ideas. TI selected their TINA simulation software over other SPICE-based simulators for its combination of powerful analysis capabilities, simple and intuitive graphics-based interface, and ease of use. The quickness of the TINA simulation software allows your circuit to be up and running in minimal time. Due to its SPICE basis, if the user is familiar with another SPICE simulator, adapting to TINA-TI is an easy and straightforward transition. Although TINA-TI is a limited version of more powerful DesignSoft simulation products, it is free software and can easily handle complex circuits. (Download at Features TINA-TI provides conventional DC, transient, and frequency domain analysis of SPICE and more. TINA has extensive post-processing capability that allows you to format results in any desired way. The included virtual instruments allow you to select input waveforms and probe circuit node voltages and waveforms. TINA's schematic capture is truly intuitive. The complimentary version, TINA-TI, is fully functional, but does not support some other features available with the full version of TINA. The installation requires approximately 200MB of memory, is straight-forward, and the final download can be uninstalled easily.

3 Applications Many application schematics are included in TINA-TI, which makes it one the fastest and easiest ways to get started with circuit simulation. You can modify these schematics and save your own changes. These Application Schematics will also run on full versions of TINA and are configured to run the analysis type shown in the example. These files are available in the examples folder of the TINA-TI program software. Application Schematic categories include: -Amplifiers and Linear Circuits -Audio (Audio Op Amp Filters, Microphone Pre-Amplifiers) -Cap Load Comp (C-oad Compensation, Line Driver) -Comparator (Comparator Circuits) -Control Loop (PI Temp Control) -Current Loop (4-20mA, 0-10mA) -Current Measurement (Current Transformer, Shunt Measure) -Difference Amps (Difference Amplifiers) Differential to Single-Ended (Differential Input to Single-Ended -Output, Single-Ended Input to Differential Output, etc) -Filters FilterPro (Multiple FeedBack, Sallen-Key: synthesized by FilterPro) -Filters Others (All-Pass, Low-Pass, High-Pass, Tunable, Twin-Tee) -Oscillators (Wien-Bridge) -Power Amps (Laser Driver, TEC Driver, Parallel Power, LED Drivers, Photodiode Driver) -Precision (Low Drift, Low Noise, Low Offset, Voltage Divider) -Sensor Condition (Thermistor, Resistive Bridge, Capacitive Bridge, Inst Amp Filter) -Signal Process (Peak Detector, Clipping Amplifier) -Single Supply (Single Supply Op Amp Circuits) -Test (Cap Multiplier, Adjust Voltage Reference, Universal Integrator, Load Cancellation, x1000 Zoom -- Amp, Quasi-Coupled AC Amp) -Transimpedance (Photodiode, Optical Detector) -Voltage-to-Current (Voltage to Current, Current to Current) -Wideband (Wideband Op Amp Circuits) -SMPS (Switched Mode Power Supplies) -Reference Designs from device evaluation modules (EVMs) for SMPS Devices Tutorial The Schematic Editor Figure 1 below shows the schematic editor layout. The empty workspace on the sheet is the design window where you will build your circuit. Below the Schematic Editor Title bar is an operational menu row with selections such as file operations, analytical operations, and test and measurement equipment selection. Located just below the menu row is a row of icons associated with different file and TINA tasks. The final row of icons allows you to select a specific component group. These component groups contain basic passive components, semiconductors, and even sophisticated device macromodels. These groups are accessed to build the circuit schematic.

4 Figure 1. TINA-TI Shematic Editor Display Building a Circuit Schematic To illustrate how to use TINA-TI, we will build an analog circuit and demonstrate some of the circuit analysis capabilities. For this example, we will use a high-output, 1kHz sine wave oscillator circuit. We will build and simulate a Wien-bridge oscillator with amplitude stabilization using the software. A Texas Instruments' OPA743 12V CMOS op amp is selected for the circuit application. This amplifier is wellsuited for this design, and provides very good dc and ac performance. It operates with supplies of 3.5V to 12V; our example requires ±5V (10V). Using Figure 2 (shown below) as a reference, select the Spice Macros tab and then the op amp symbol to access the OPA743 macromodel. When the op amp model list appears, scroll down and click on the OPA743. Then click OK. The op amp symbol appears in the circuit workspace. With the mouse, drag the symbol into position. It is locked into position on the circuit workspace by clicking the left mouse button.

5 Figure 2. Circuit Build Example Other op amp models may be selected using the Insert->Macro menu. Additionally, macros and a wide variety of pre-built analog and SMPS circuits can be accessed through the Insert menu. Using Passive and Active Components Component selection is easily accomplished by clicking on a component group from the lower row of tabs. These tabs provide a wide variety of passive components, sources, meters, relays, semiconductors, and the previously-mentioned circuit macros. Click on the schematic symbol for a particular component and drag it into position in the circuit workspace. A left mouse button click locks it into place. In our example, using Figure 3 as a reference, we select a resistor from the Basic tab group then position it next to the op amp symbol. TINA-TI designates this resistor as R1. The initial value of R1 is 1kΩ, but this value can be changed as needed. A double-click with the left mouse button on the R1 symbol produces the associated component table. These steps are illustrated below, in Figure 3.

6 Figure 3. Active/Passive Component Selection The resistor value and other component characteristics may be altered by selecting the individual parameter boxes and changing the respective values. To do this, select the component parameter box and highlight the value you wish to change. Enter a new value by typing over the value that is shown. In Figure 3, for example, the value for R1 has been changed from 1k to 4.7k for this circuit. Similar parametric tables are available for passive devices, sources, semiconductors, and other component types. Once all components are selected and properly positioned, they can be wired together. Wiring components to each other is easily done by placing the mouse pointer over a node connection and holding the left mouse button down. A wire is drawn as the mouse is moved along the circuit space grid. Figure 4 below shows the circuit after wiring is complete and can be used for reference.

7 Figure 4. Wired Components Analysis When the circuit schematic entry is complete, the circuit is nearly ready for simulation. The analysis process begins by selecting the Analysis menu. A list of different types of analyses such as ac, dc, transient, or noise appears. Highlight any one of these evaluations to access additional options and selections. For DC Analysis, click on the Analysis menu, select DC Analysis, and click on the Table of DC Results. When the Voltages/Currents table appears, you can use the mouse pointer as a probe to test the circuit nodes. Figure 5 below shows DC Analysis with the Voltages/Currents table displayed and can be used as a reference.

8 Figure 5. DC Analysis with Voltages/Currents table For Transient Analysis, ac frequency and time domain simulations may also be performed. Click on the Analysis menu, select Transient, and the Transient Analysis dialog box appears. Enter start and end times, and other parameters as desired and then click ok. Figure 6 below is a transient analysis performed on the example Wien-bridge oscillator circuit. The simulation transient analysis result is also shown in Figure 6. It illustrates the Wien-bridge oscillator startup and steady-state performance. The display in the actual window may be edited with axis labeling, scales, background grid color, and so forth, all set as desired by the individual user.

9 Figure 6. Transient Analysis Capabilities Testing and Measurements The TINA-TI software generates post-simulation results in tables and plots, depending on the type of analysis performed. Additionally, the software can be placed in a pseudo-real-time simulation mode where virtual instruments can be used to observe the output while the circuit is operating. For example, Figure 7 shows a virtual oscilloscope that is used to observe the steady-state output of the Wien-bridge oscillator circuit. In the same way, a virtual signal analyzer can be used together with an amplifier circuit so that the harmonic performance of a simulation can be observed. To access the virtual oscilloscope, select T&M (step 1) and then Oscilloscope (step 2) as labeled below in Figure 7. Place the cursor at the output of the simulated circuit, and adjust the controls in the virtual oscilloscope dialog box as needed (step 3). The T&M selection options also include a virtual ac/dc multimeter, function generator, and an X-Y recorder. The function generator may be adjusted in combination with a virtual oscilloscope or analyzer.

10 References: Figure 7. Virtual Implementation Testing