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Many times, you would have required to create a standard pulse waveform that can be used for testing devices as per the industry standard.

One good example is to simulate the ISO 7637-2 transient at the schematic design stage. This practice ensures that problems are identified much before the electromagnetic compatibility (EMC) testing phase thus preventing design time and cost escalations.

While simulating in PSpice^® A/D, you can generate a simple impulse or repetitive pulse waveforms for an electronic circuit that can be used for testing and analysis of various automotive products or consumer electronics.

In this blog post, we will see an easy way to generate an ISO 7637-2 Standard Pulse 2a using two PSpice A/D Modeling Applications, namely Independent Sources and PWL Sources. So, let’s get started.

Placing a Voltage Source

1) Open a simulation design in OrCAD Capture, or create a project.

2) To add a Pulse source, click  to open the modeling application pane and then select Independent Sources. 

3) The following figure shows the ISO 7637 Pulse 2a waveform.

To generate this ISO 7637-2 Standard Pulse 2a waveform using the Independent Sources application, select the Exponential voltage source and specify the parameter values as shown below.

4) Click Place.

5) Place the voltage marker using  on the PSpice toolbar.

6) Simulate the design.

You see the waveform for a single pulse.

Generating Multiple Pulse Waveform

Now, to generate multiple pulses in the time domain, you need to perform the following tasks:

1) Export this single pulse waveform as a text file. To do so, select File – Export – Text.

    The Export Text Data window appears.

2) Select a text file to export the pulse data.

3) Click OK.

    This text file contains the time value pair for this single wave.

4) Edit this text file to remove the header information.

5) Use this text file to create multiple pulses using the PWL Sources modeling application. To do so, you need to add a PWL voltage source to the design and specify the signal repetition.

6) From the modeling application pane, access the PWL Sources application.

7) In the PWL File field, browse the exported and edited text file in step 4.

8) Select Repeat Forever under the Signal Repetitions section.

9) Click Place.

10) Place the voltage marker using  on the PSpice toolbar.

11) Simulate the design.

      Multiple pulses are seen in the waveform.

I am sure with this example, you can see the benefits of using the source modeling applications, especially how it helps to quickly generate the ISO 7637 Pulse 2a waveform in PSpice A/D. Using similar methodology, you can generate a simple impulse or repetitive pulses as per your requirement.

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