An Envelope-Following Approach to Switching Power Converter Simulation

Simulating the transient behavior of switching power converter circuits is computationally expensive because these circuits are clocked at a frequency whose period is orders of magnitude smaller than the time interval of interest to the designer. It is possible to reduce the simulation time without compromising much accuracy by exploiting the property that the behavior of switching converters in a given high-frequency clock cycle is similar, but not identical, to the behavior in the preceding and following cycles. In particular, the envelope of the high-frequency clock can be followed by accurately computing the circuit behavior over occasional cycles. In this paper the implementation of an envelope-following method that is particularly efficient for open-loop switching power converters with fixed clock frequencies is described, and results demonstrating the method’s effectiveness are presented.