Frequency response of switching DC/DC converters from a single simulation in the time domain

In this paper, a simple method to obtain the frequency response of a switching DC/DC converter is proposed. The Bode plot is obtained from a single simulation in the time domain using the switching model of the power converter, and injecting a multisine perturbation. The procedure to generate the perturbation, simulate the converter and post-process the response is explained. It is applied to several simulators, both analog (OrCAD/PSPICE, PSIM) and digital (ModelSim), and different DC/DC converters (open-loop and closed-loop). The main advantage of the proposed approach is the important saving in simulation time compared to a single-tone injection approach.