Designing for Efficiency
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9.3 Configuring Transient Analysis Settings
Open the simulation profile editor and verify the transient analysis configuration:
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Analysis type: Time Domain (Transient)
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Simulation run time: long enough to reach steady state
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Maximum time step: sufficiently small to capture switching transitions
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Skip initial bias point (if enabled) consistent across profiles
The run time must allow startup transients to decay so that the steady-state waveform behavior shown in Figure 2 can be
accurately reproduced. Efficiency measurements are taken only after periodic steady state is established.
9.4 Running the Transient Simulation
Run the simulation using PSpice → Run.
During execution:
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Monitor the simulation status window for convergence warnings
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Allow the simulation to complete fully before taking measurements
Once complete, the waveform viewer opens automatically and displays synchronized waveforms similar to those presented in
Figure 2.
9.5 Loading Saved Measurement Displays
To load the predefined measurement environment:
Select:
Window → Display Control
and load the saved display set named:
loss_eff_calc
This display contains synchronized plots for:
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Overall efficiency
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Input power
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Output power
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Switch loss
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Diode loss
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Output voltage and current
These synchronized waveforms correspond to the layout shown in Figure 2. Using a saved display ensures consistent
measurement methodology between runs.
9.6 Measuring Steady-State Efficiency
Place cursors in the waveform viewer over a steady-state interval where waveforms are periodic, as demonstrated in
Figure 2.
For the reference design, a typical window is:
4.86 ms to 4.90 ms
Average values displayed in the cursor readout correspond to:
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Time-averaged input power
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Time-averaged output power
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Calculated efficiency
