Derivation of the sliding domain for a buck-based switching amplifier in wideband signal tracking applications

Abstract

One of the major drawbacks that precludes the use of sliding-mode control wideband signal tracking in buck-based switching power amplifiers is the lack of a design-oriented analysis of tracking bandwidth limits. In this paper the tracking limits for a linear-surface sliding-mode controlled ideal buck converter are addressed for different representative cases, namely, for a single tone, two tones, multiple tone, and a generalization to an arbitrary wideband signal. Analytical design-oriented equations are matched with simulations both for synthetic single-tone and arbitrary wideband noise signal as well as for the envelope signal corresponding to the EDGE standard in an envelope elimination and restoration technique polar RF transmitter architecture.