DER-256: 300mA @ 50V Max, 90 ~ 265VAC in

Summary

The document describes a power factor corrected LED driver designed to drive a nominal LED string voltage of 50 V at 0.3 A from an input voltage range of 90 VAC to 265 VAC. The LED driver uses the LNK406EG from the LinkSwitch-PH family by Power Integrations.

LinkSwitch-PH ICs allow the implementation of cost effective and low component count LED drivers which meet both power factor and harmonics limits; and also offer an enhanced end user experience.
This includes ultra-wide dimming range (not used in this demo), flicker free operation (even with low cost AC line TRIAC dimmers) and fast, clean turn on.

The topology used is an isolated flyback operating in continuous conduction mode. Output current regulation is sensed entirely from the primary side eliminating the need for secondary side feedback components. No external current sensing is required on the primary side either as this is performed inside the IC further reducing components and losses. The internal controller adjusts the MOSFET duty cycle to maintain a sinusoidal input current and therefore high power factor and low harmonic currents.

The LNK406EG 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, output overvoltage protects the supply should the load be disconnect and accurate hysteretic thermal shutdown ensures safe average PCB temperatures under all conditions.

The key goals of this design were low profile and high efficiency. This was to allow the driver board to fit into the space behind the LED load board inside a T8 tube and operate with an acceptable temperature rise. This necessitated careful selection of components and mounting methods but was simpler than alternate solutions due to the low component count required for a primary side regulated LinkSwitch-PH design.

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

Specifications

Manufacturer Power Integrations
Category Lighting
Sub-Category LED Drivers - AC / Offline
Eval Board Board not Stocked
AC Voltage 115 V
230 V
Universal
Outputs and Type 1 Isolated
Current Out 300 mA
Voltage Out (Max) 55 V
Efficiency @ Conditions >86%, 115 ~ 265 VAC, @ 50 V
Features Current Limit (Adj. or Fixed)
Dimming Control
Frequency Jitter for EMI
Open Circuit Protection
PFC
Short Circuit Protection
Thermal Protection
Switching Frequency 66 kHz
Component Count + Extras 49 + 0
Design Author Power Integrations
Application / Target Market Lighting: LED Commercial Lighting
Lighting: LED Home Lighting
Voltage In 90 ~ 265 VAC
Power Factor >0.9
Standard(s) EN61000-3-2 Class D (C)
IEC 61000-3-2 Class C
Main I.C. Base Part LNK406
Date Created By Author 2010-10
Date Added To Library 2014-08