DER-314: 425mA @ 36V Max, 185 ~ 265VAC in

The document describes an isolated high power factor (PF) TRIAC dimmable LED driver designed to drive a nominal LED string voltage of 36 V at 425 mA from an input voltage range of 185 VAC to 265 VAC. The LED driver utilizes the LNK406EG from the LinkSwitch-PH family of ICs.

Key goals for this design were:
• Lowest cost
• Small size
• Efficiency
• Demonstration of (optional) thermal fold back (output current reduces above temperature threshold)

The topology used is a single-stage power factor corrected flyback, that delivers high efficiency, high power factor, low THD, isolation, low component count, and meets the stringent space limits for this design.

High power factor and low THD is achieved by employing the LinkSwitch-PH IC which also provides a sophisticated range of protection features including auto-restart for open control loop and output short-circuit conditions. Line overvoltage provides extended line fault and surge withstand, and accurate hysteretic thermal shutdown that ensures safe average PCB temperatures under all conditions.

This document contains the LED driver specification, schematic, PCB diagram, bill of materials, transformer documentation and typical performance characteristics.