32 ECEN5807 Intro to Converter Sampled-Data Modeling Conclusions PWM is a small-signal sampler Switching converter is a sampled-data system Duty-cycle perturbations act as a string of impulses Converter response to the duty-cycle perturbations can be modeled as an equivalent hold Averaged small-signal models are low-frequency approximations to the equivalent hold In DCM, at high frequencies, the inductor-current dynamic response is described by an equivalent hold that behaves as zero-order hold of length D 2 T s Approximate continuous-time model based on the DCM sampled-data model correlates with the analysis of Section 11.3: the same high-frequency pole at f s /(  D 2 ) is obtained Next: current-mode control (Chapter 12)
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