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Constant on/off-Time Hybrid Modulation in Digital Current-Mode Control Using Event-Based Sampling.
- Source :
-
IEEE Transactions on Power Electronics . Apr2019, Vol. 34 Issue 4, p3789-3803. 15p. - Publication Year :
- 2019
-
Abstract
- Ripple-based constant on-time and off-time control techniques can achieve fast step-down and step-up transient performance along with an improved light-load efficiency. However, they suffer from varying switching frequency at the steady state and often require a phase-locked loop for frequency regulation. This paper proposes a constant on/off-time hybrid modulation technique in a digitally current-mode controlled synchronous buck converter. The proposed technique considers an event-based sampling mechanism using one sample per switching cycle, which makes it useful for high-frequency implementation. This requires a monoshot timer and a digital voltage controller $G_c(z)$. The proposed technique can be configured to a constant on-time or off-time modulator with seamless transition because of sharing $G_c(z)$ ; thus, improved step-up/down transient performance can be retained. Furthermore, a discrete-time framework is proposed for fast-scale stability analysis, and the effects of finite sampling and practical parasitics are discussed. Discrete-time small-signal models are derived for the direct digital control design with enhanced stability and performance. A frequency adaptation method is discussed to customize the switching frequency in real time. A buck converter prototype is tested, and the usefulness of the proposed modulation technique is verified experimentally. [ABSTRACT FROM AUTHOR]
- Subjects :
- *CASCADE converters
*DIGITAL modulation
Subjects
Details
- Language :
- English
- ISSN :
- 08858993
- Volume :
- 34
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- IEEE Transactions on Power Electronics
- Publication Type :
- Academic Journal
- Accession number :
- 135356410
- Full Text :
- https://doi.org/10.1109/TPEL.2018.2849608