This manual provides detailed reference material for the SIMPLIS (SIMulation for Piecewise-LInear System) simulation package. It is intended for those who want to develop a more in-depth understanding of this software package.

SIMPLIS is a computer software package specifically designed for the simulation and analysis of switching power supplies. In a typical switching power system, the transistors and the diodes function as switches, allowing the system to be characterized by a cyclical sequence of linear circuit topologies. By taking advantage of the repetitive piecewise-linear structure of such systems, SIMPLIS is able to perform the simulation in an efficient and accurate manner.

In order to avoid potential problems caused by simple syntax errors, SIMPLIS automatically checks the syntax of the input file provided by the user. If syntax errors are detected in the input file, error messages are recorded in a file for the user to inspect and correct the errors. This feature allows the user to detect and correct errors quickly and efficiently.

SIMPLIS-TX is a two-pass time-domain simulator. In the first pass of a simulation run, only the data pertaining to the state of the simulation at the switching instances are saved. In the second pass, called the Post-Simulation Processing run, detailed waveform information is reconstructed from the data generated in the first pass. At the user-interface level, these two separate operations are not distinguishable since they are executed automatically by SIMPLIS. Thus SIMPLIS appears as a one-pass simulator to the user. This internal two-step simulation technique optimizes the simulation speed and versatility of SIMPLIS.

SIMPLIS-POP (Periodic Operating Point) is an analysis tool that accelerates the convergence to the steady-state solution of switch-mode power systems. By taking into consideration the variation of the timing of the intracycle intervals of a switch-mode system with respect to changes in the state vector, the POP analysis tool accurately calculates the steady-state solution.

SIMPLIS-FX is a special small-signal frequency-domain analyzer developed for the analysis of switching power supplies. By calculating the circuit's response, over a range of frequencies, to a small perturbation in the time domain and then using fast fourier analysis techniques, the necessity of developing state-space averaged equivalent circuits is avoided. SIMPLIS-FX accurately computes the frequency response from the same schematic used for time-domain simulation.