Current-Loop Control in Switching Converters Part 3: Waveform-Based Model Dynamics

Focus:

In this article, development of a unified model of current-mode control continues with the derivation of the dynamic equations for transfer functions of blocks in the current loop. Here in part 3, the author transforms the discrete-time equations from part 2 to the z-domain and pass quickly through it to the sampled s-domain. Conversion of the waveform equations to the z-domain is straightforward and lets the author derive a closed-loop transfer function of the peak-current controller. Dynamics equations are derived for both the valley-current samples and for the average inductor current for each switching cycle. By deriving the transfer functions for the average current, a new refined model begins to emerge that shows a somewhat different response than the familiar valley-current model.

What you’ll learn:

• How to understand Dennis Feucht’s derivation of key equations necessary to the development of his refined unified model of current-mode control

View the Source

Author & Publication:

Dennis Feucht, Innovatia Laboratories, Cayo, Belize, How2Power Today, Nov 30 2011

This article summary appears
in the HOW2POWER Design Guide.

The Design Guide offers
organized access to
hundreds of articles
on dozens of power conversion
and power management topics.

The Design Guide search results
include exclusive summaries
and accurate "how to" analysis
to help you make faster,
more informed decisions.

Search
for more articles