TINA-TI(TM) Waveform Viewer, Part 1
Learn about the powerful features of TINA-TI's waveform viewer to display and interpret your simulation results.
Resources
Welcome to this video tutorial on tina-ti, the free SPICE simulator from Texas Instruments. In this video, you'll learn about some of the powerful features available in tina-ti's waveform viewer to display and interpret your simulation results.
In order to see waveforms from points in your circuit, you have to add meters to the circuit. This bipolar input differential output single supply circuit found in the examples folder of tina-ti has two metering points shown, Vout and Vout prime. When drawing your schematic, you add these from the meters tab on the toolbar.
The metering point is on the extreme left and is what is most commonly used in our examples schematics. Since what the analog to digital converter this circuit will drive sees is the difference between these two points, we can add a volt meter between the two outputs to show us the difference between the two nodes.
Our circuit is now set up to show us the two outputs, Vout and Vout prime referenced to ground and the difference between the two, Vm1. War Let's run a transient simulation and see what happens. Note that you have the option of also displaying the exitation when running a transient analysis.
All of the signals are plotted on one graph. This is sometimes not the way you want to see things. You can have each signal in its own graph by selecting view, separate curves. You can bring them all back into one graph by selecting view, collect curves.
Note that the graph's auto scaled with the minimum and maximum values of the signal. If you want a specific range on an axis, double click on it and the set axis window will open. You can then enter the minimum and maximum values, as well as change the number format, scale type, and number of ticks shown on the scale.
You have a lot of control over how the graph is presented, but notice how the Vm1 output is above the Vn curve when we separate curves. We'd instead like to have Vn at the top, and it would be nice if the viewer would automatically separate the curves for us.
You can tell tina-ti to automatically separate curves, and the order to put them in by adding a colon and number in the label. This works for the exitation as well as for the meters.
Now when we run our transient analysis, Vn is at the top, followed by Vout and then Vout prime. Vm1 ends up at the bottom.
You can use cursors to find the value of a point on a waveform. Simply select a cursor and click on the waveform you want that cursor associated with. Using the cursors, you can see the values at different points on the waveform, and you can see the difference between them. You can also enter a time value in the cursor display to position the cursor exactly at a specific time point. You can place cursors on different waveforms, too.
When you have your graphs formatted as you like them, you can export the graphs using the file export function. You can save as a Windows Metafile Format, bitmap, or jpeg.
You can then use the saved graphic file in programs like Microsoft Word or PowerPoint to share your results. You can even bring the graphic onto your schematic.
Using the insert graphics menu selection, you can choose the file you just saved and place it on your schematic to document the results. You can also export the raw data from the curves by selecting file, export as text. Doing this will save a file that you can open in Notepad or bring into a spreadsheet, like Microsoft Excel.
With the simple graphs we have from this circuit, we've done a lot of things. Let's look at one more capability that will help you examine your results.
This switching power supply circuit is set up to show us the start up behavior of the TPS54331. Let's run a transient analysis and see the results.
The waveform at the top of the display is the switching waveform, Vn is the input voltage, and Vo is the output of the supply. You can see from this how the output ramps as the supply begins regulating.
Let's say you want to see what happens during the beginning of this sequence. You can select the zoom tool and select a region to zoom in on. You can see a little more detail on that. You can zoom both x and y by dragging the box. You can also reset to the full view by selecting the normal zoom tool.
These are just a few of the powerful features of tina-ti's waveform viewer. We'll explore some more features in a future video. Thanks for watching this video tutorial on tina-ti.