Accelerated convergence to Periodic Steady State of SMPS circuits using PSpice

The periodic steady state (PSS) of switched mode power supplies (SMPS) is of great interest to the analog designers since it serves as a starting point for further frequency response, noise and distortion analysis. Traditionally, to reach such a periodic steady state through PSpice, the designer must run the transient simulation and wait for the system to settle to its steady state. This takes a long time because SMPS circuits are stiff circuits with a wide range of time constants. In this work, we present how accelerated convergence to PSS has been achieved in PSpice. We have enabled three prominent algorithms to achieve PSS - Minimum Polynomial Extrapolation (MPE), shooting-Newton method using Numerical Jacobian, and shooting-Newton method using Analytical Jacobian. In this paper, we present these state-of-the art algorithms and their customizations in the PSpice simulator, along with the successful results obtained on a range of circuits.