High-Power-Density LED Drivers based on Magnetic Integration

Abstract

In this paper, the idea of magnetic integration for LED drivers is investigated. A study of two integrated converters is carried out, namely the Integrated Buck and Boost Converter (IBBC) and the Integrated Parallel Buck-Boost and Boost Converter (IPB3C). Both converters show excellent operating features such as high Power Factor (PF), low Total Harmonic Distortion (THD), high efficiency, and high power density. The IBBC is a cascade two-stage converter that features all benefits of two-stage converters, but with the benefit of requiring only one switch. Concerning the IPB3C, it is a parallel two-stage converter that exhibits low double processing of power and output ripple reduction, keeping also only one controlled switch. Furthermore, the IPB3C can fulfill the standards of LED current ripple while making it possible to avoid the use of electrolytic capacitors in the converter. For the sake of higher power density and higher efficiency, the magnetic integration technique is applied to these two converters, producing the Fully Integrated Buck and Boost Converter (FIBBC) and the Magnetically-Integrated Parallel Buck-Boost and Boost Converter (MIPB3C). In this paper, the FIBBC as well as the MIPB3C are magnetically analyzed. Two prototypes supplying an LED luminaire of 46 V/ 0.575 A and 78 V/ 0.350 A, based on the FIBBC and MIPB3C, respectively, are presented. Both prototypes show a high PF of more than 0.99, very small THD of less than 6 %, output current ripple in the limits specified by the standards, and efficiency of 92.4% and 93.65 % for the FIBBC and the MIPB3C, respectively, which represent a landmark of the efficiency of integrated converters, previously reported in the literature.