LM3450AEV230V30: 700mA @ 45V Max, 180 ~ 265 VAC

The LM3450A evaluation board is designed to provide an AC to LED solution for a 30 W LED load. Specifically, it takes an AC mains input and converts it to a constant current output of 700 mA for a series string of 1 to 13 LEDs (maximum LED stack voltage of 45 V). There are two assembly versions designed to operate from two different nominal AC input voltages, 120 VAC or 230 VAC.

The board employs a two stage design with an LM3450A flyback primary stage and an LM3409HV secondary stage. The LM3450A provides an isolated 50 V regulated output voltage and a power factor corrected input current. The LM3409HV uses the 50 V flyback output as its input and provides a constant current of 700 mA to the LED load. This two stage design provides excellent line and load regulation as well as isolation. The board is comprised of two copper layers with components on both sides and an FR4 dielelectric.

The two-stage design has several key advantages over a single stage design including: no 120 Hz LED current ripple, better dimming performance at low dimming levels, better line disturbance rejection, and better efficiency using small LED stack voltages.