DN05055/D, Compact 90 - 135 VAC Hi-PF Boost LED Driver Design Note

DN05055/D, High Voltage LEDs are becoming more popular and are now available from multiple LED manufacturers. These package LEDs may have typical forward voltages ranging from 24 to >200 V. The development of these types of LEDs has been driven in part by the desire to improve the power conversion from the AC mains voltage to the LED string voltage as well as simplifying the driver electronics. In fact in some cases they have been promoted as being driver-less since a diode bridge and linear regulator can implement a very simple circuit. There are several drawbacks to this approach. As the LEDs are off for a portion of every line cycle when the input voltage is below the LED forward voltage, more LEDs are needed to produce the desired lumen output