Sampled-Data Modeling and Analysis of the Power Stage of PWM DC-DC Converters
Abstract
The power stage of the PWM DC-DC converter is modeled and analyzed using the sampled data approach. The work addresses continuous and discontinuous conduction mode under voltage mode control, and continuous conduction mode under current mode control. For each configuration, nonlinear and linearized sampled-data models, and control-to-output transfer function are derived. Using this approach, both current mode control and discontinuous conduction mode can be handled systematically in a unified framework, making the modeling for these cases simpler than with the use of averaging. The results of this paper are similar to results of Tymerski, but they are presented in a simpler manner tailored to facilitate immediate application to specific circuits. It is shown how sampling the output at certain instants improves the obtained phase response. Frequency responses obtained from the sampled-data model are more accurate than those obtained from various averaged models. In addition, a new ("lifted") continuous-time switching frequency-dependent model of the power stage is derived from the sampled-data model. Detailed examples illustrate the modeling tools presented here, and also provide a means of comparing results obtained from the sampled-data approach with those obtained from averaging.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1999
- Accession Number
- ADA438683
Entities
People
- Chung-chieh Fang
- Eyad H. Abed
Organizations
- University of Maryland