Quickstart

In about ten minutes, you will open a working buck converter, change it, run it again, measure its ripple, and save it. You do not need to install anything or create an account.

1. Open a working converter

Open the buck CCM example and choose Open and simulate. The app opens the template, adds an output-voltage probe, and runs it once.

The workspace has three panels:

• Circuit shows the schematic, component settings, and connections.
• Waveforms contains probes, calculations, cursors, measurements, and the frequency spectrum.
• Analysis contains startup, periodic steady state, saved measurements, and parameter sweeps.

The model information in the header shows the accuracy level and model type used for the result. A completed run never changes them without telling you.

2. Change something and run it again

Select switch S1 and change its duty from 0.18 to 0.22. Choose Run design. The second result now reflects your change, so you can compare it with the original example.

The status area shows setup and simulation progress. If the selected model cannot solve the circuit, the app explains the problem and suggests a fix. It does not silently switch to another model.

3. View the result

Choose Probe, then select the output wire to add v(out). Select an inductor to add its current. You can also enter a calculation such as:

v(out)*i(L1)

Put signals with different units in separate panels. Use the mouse wheel or a pinch gesture to zoom in time. The Y-axis controls change one panel, and Frame shows the whole run again.

4. Measure the waveform

Place cursors A and B around a stable section of the waveform. PWMSim shows the cursor values, average, RMS, minimum, maximum, and peak-to-peak. The spectrum uses the raw data inside the selected range. It is unavailable when the full raw data is not available.

In Analysis, save a measurement such as peak-to-peak of v(out) over the last period. PWMSim recalculates it after each later run and at every point in a parameter sweep.

5. Solve periodic steady state

Choose Periodic steady state in Analysis and run it. For a supported circuit with one switching period, PWMSim solves the repeating behavior directly and reports how closely it repeats. If the circuit has no supported single period, PWMSim stops and explains why.

6. Test several parameter values

In Parameter sweep, choose a component setting and enter values such as 0.16, 0.18, 0.20, 0.22. PWMSim tests each value in order. Failed points stay visible in the table instead of disappearing from the chart.

7. Import, save, share, and export

• Import accepts supported SPICE files (.cir, .net, .spice, or text). The import report lists exact, changed, and unsupported parts.
• Projects save automatically in your browser. You can also import or download a versioned project file.
• Share puts the circuit in the URL fragment, so the circuit is not uploaded.
• Export creates a project file, a portable netlist when possible, a schematic image, or a complete evidence report.

Next, browse the examples, check the LTspice validation results, or read the supported features and limits.