This Help topic book contains information about SIMPLIS device models, as well as a general overview of the modeling techniques employed in SIMPLIS.

SIMPLIS Modeling Techniques

All models used in SIMPLIS are Piecewise Linear (PWL). Some common devices which are PWL include ideal resistors, capacitors and inductors. For example, an ideal resistor models a linear resistance over all voltages and currents. This is an example of a single segment PWL model. SIMPLIS also supports devices with more than one Piecewise linear segment, for example an ideal diode can be represented by two resistive segments - a high "off" resistance and a low "on" resistance. The point where the two segments meet can be set to model the forward diode drop.

Using SPICE models in SIMPLIS

Because SPICE models use non-linear equations to model device behaviors, these models cannot be directly used in the SIMPLIS simulator. For common semiconductor devices such as MOSFETs, IGBTs, diodes, etc., SIMetrix/SIMPLIS includes a set of Model Parameter Extraction routines. These routines extract SIMPLIS parameters from the SPICE model, effectively producing a SIMPLIS model which behaves similar to the given SPICE model. For more details, see the SPICE Model Installation Process topic.

Digital Devices

SIMPLIS incorporates an event driven digital simulator which runs in parallel with the conventional SIMPLIS simulator. A complete library of digital devices is documented in the SIMPLIS Digital Devices topic.

How Accurate are PWL models?

Piecewise linear models can very accurately model switching power supply behavior. Several examples comparing the simulated vs. experimental Lab data are located here