Two-stage power conversion architecture for an LED driver circuit

This paper presents a merged-two-stage circuit topology suitable for efficient LED drivers operating from either wide-range dc input voltage or ac line voltage. This two-stage topology is based on a soft-charged switched-capacitor pre-regulator/transformation stage and a high-frequency magnetic regu...

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Bibliographic Details
Main Authors: Lim, Seungbum, Ranson, John, Otten, David M., Perreault, David J.
Other Authors: Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Format: Article
Language:en_US
Published: Institute of Electrical and Electronics Engineers (IEEE) 2014
Online Access:http://hdl.handle.net/1721.1/90549
https://orcid.org/0000-0002-0746-6191
https://orcid.org/0000-0003-0313-8243
https://orcid.org/0000-0001-7022-4817
Description
Summary:This paper presents a merged-two-stage circuit topology suitable for efficient LED drivers operating from either wide-range dc input voltage or ac line voltage. This two-stage topology is based on a soft-charged switched-capacitor pre-regulator/transformation stage and a high-frequency magnetic regulator stage. Soft charging of the switched capacitor circuit, zero voltage switching of the high-frequency regulator circuit, and time-based indirect scale current control are used to maintain high efficiency, high power density, and high power factor. Two implementations of the proposed architecture are demonstrated: a wide input voltage range dc-dc converter and a line interfaced ac-dc converter. The dc-dc converter shows 85–95% efficiency at 20 W power across 25–200 V input voltage range, and the ac-dc converter achieves 88% efficiency with 0.93 power factor at 8.4 W average power.