500-V buck LED drivers use single-winding inductor

The AL1678 family of LED drivers target non-dimmable retrofit LED bulbs in general illumination applications that do not require high power factor (>0.7). These 500-V buck-converter LED drivers support output powers up to 15 W for LED lighting applications such as Class-A/B/P and GU10 lamps across all mains line voltages.

The driver provides circuit flexibility and delivers constant current line and load regulation from 85 to 277-V_AC input range. In addition, by operating in boundary-conduction mode, the driver keeps EMI low with 90% efficiency. The AL1678 LED drivers’ total BOM lamp cost is low because it removes the need for an external high-voltage MOSFET and an auxiliary winding, while requiring only a single external inductor. Integrated protection features include under-voltage lockout, over-temperature protection, LED open- and short-circuit protection, as well as a thermal fold-back function.