A long-life high-power-factor HPS-lamp LED retrofit converter based on the integrated buck-boost buck topology

In this paper a long-life high-power-factor integrated converter able to supply LED lamps in high-pressure-sodium (HPS) lamp retrofit applications is presented. The converter is made up by the integration of a buck-boost converter with a buck converter, which provides the necessary high input power factor and low voltage transformation ratio to supply the low-voltage LED array from the mains. The analysis of the converter is carried out and a design procedure is proposed. Also, the design is performed so that low capacitances are needed at the output of each semistage. This allows for the use of long-life film capacitors, thus matching the converter lifetime to that of the LED lamp. A laboratory prototype supplied from 230V/50Hz mains used to drive two LED arrays in series with a total output power of 100W is presented.