How do I view Bode plot in LTspice?

Table of Contents

Run your simulation (see bottom left corner for status update).
To view the Bode plot, open the SPICE Error Log (choose SPICE Error Log from the View menu) and right-click on the log to select “Plot . step’ed . meas data”. Choose Visible Traces from the Plot Settings Menu. Select gain.

How do you use LTspice to produce Bode plots for LED drivers?

To create a full Bode plot, a graphical sweep of gain and phase, in LTspice for the control loop, follow these steps.

Step 1: Create the AC Injection Source.
Step 2: Add the Math.
Step 3: Set the Measurement Parameters.
Step 4: Set the Frequency Sample Step and Range.
Step 5: Run the Simulation.
Step 6: Produce the Bode Plot.

How does AC analysis work?

AC Analysis is used to calculate the small-signal response of a circuit. In AC Analysis, the DC operating point is first calculated to obtain linear, small-signal models for all nonlinear components. Then, the equivalent circuit is analyzed from a start to a stop frequency.

How do you plot a graph in LTspice?

LTspice: Parametric Plots

Click on a node/component to plot its voltage/current in the waveform viewer.
Move the cursor to the horizontal axis of the waveform viewer (the cursor will turn into a ruler) and right-click.
In the Horizontal Axis dialog, enter an expression for the “Quantity Plotted.
Click OK.

How do you plot gain in LTspice?

Plotting the Voltage Gain Use expressions to plot the voltage gain of the circuit. Right-click on “V(vout)” in the plot window and change the text in the dialog box to “V(vout)/Vi”. This plots the large-signal gain of the circuit shown on the right.

What is AC sweep analysis in LTspice?

In LTspice, AC analysis involves computing the AC complex node voltages as a function of frequency using an independent voltage or current source as the driving signal. The small signal analysis results are plotted in the waveform viewer as magnitude and phase over frequency.

What is AC sweep analysis?

An AC analysis calculates the small signal response of a circuit to any number of user defined inputs. The small signal response is computed by treating the circuit as linear about its DC operating point.

What is the difference between DC analysis and AC analysis?

AC analysis gives the voltage or current versus frequency in a linearized version of the circuit. DC analysis gives DC voltage or current, usually versus a stepped voltage or current. In principle, each analysis should give results that agree with the others, if looked at correctly.

Why do we use AC and DC analysis?

AC analysis gives u the output and other values when an A.C supply is provided to the designed circuit. DC analysis gives u the output and other values when an D.C supply is provided to the circuit. Transient analysis is most useful for studying fault conditions in the circuit, like short circuits, overloads, etc.

How do I view the Bode plot in spice?

To view the Bode plot, open the SPICE Error Log (choose SPICE Error Log from the View menu) and right-click on the log to select “Plot .step’ed .meas data”. Choose Visible Traces from the Plot Settings Menu. Select gain. From this plot you can then determine the crossover frequency and phase margin of your SMPS design.

How to perform frequency response analysis (FRA) of SMPs In LTspice IV?

Using the voltage gain portion of the Middlebrook method is particularly useful in performing a frequency response analysis (FRA) of an SMPS in LTspice IV. Insert a voltage source with a value of “SINE (0 1m {Freq})” in the SMPS feedback loop in series with the feedback pin and label the nodes of this voltage source “A” and “B” as shown.

How do I get Bode data from the Spice error log?

Open the SPICE Error Log by right-clicking the schematic window and choosing Plot .step’ed .meas data. Choose Visible Traces from the Plot Settings Menu and select Gain to plot the data. Optionally, measurement data can be exported by clicking File and selecting Export Data as Text to produce a CSV file of the Bode data.

How do I make a Bode plot from a schematic?

Follow the next steps to produce the Bode plots. Open the SPICE Error Log by right-clicking the schematic window and choosing Plot .step’ed .meas data. Choose Visible Traces from the Plot Settings Menu and select Gain to plot the data.