Acquisition of small-signal frequency-domain measurements from switch-mode power supplies

An algorithm is presented for selecting an appropriate perturbation amplitude for acquisition of small-signal frequency-domain characteristics from switch-mode power supplies. Among a range of perturbation amplitudes, measured data characteristics are categorized as linear or nonlinear, based on user-specified tolerances. This algorithm is especially useful for computer-aided measurements which permit on-line control of the perturbation amplitude. The work represents one portion of a complete computer-aided measurement system containing hardware and software specifically designed to support the general sapes of measurements important to the design and analysis of switch-mode power supplies.