RD-172 - Off-Line TRIAC Dimmer LED Driver Reference Design
Design Specifications
Inputs Outputs #1
VinMin = 90 VAC Vout1 = up to 32V
VinMax = 230 VAC Iout1 up to 350 mA

Design Description

This reference design converts 90 VAC to 135 VAC input, and drives seven, or eight series connected LED's from 300 to 600 mA average current.. The LM3445 switching frequency is set at a nominal 225 kHz. This is a four layer board using the bottom and top layer for component placement. The reference design can be modified to adjust the LED forward current, the number of series connected LEDs and switching frequency.

A secondary schematic for a 230 VAC implementation is also included.

   Design Resources
• RD-172 Reference Design Document
•  CAD Design Files (Altium Designer source schematic and board layout)
  LM3445 TRIAC Evaluation Board
(120V version)

LM3445 TRIAC Evaluation Board
(220V version)

Additional Product Resources

• LM3445 - Triac Dimmable Offline LED Driver
  • datasheet
  • application notes
  • Webench Online design tools
  • samples

Board Photo

RD-172 Board Photo
   Features

  • No flicker even at very low dim ratios

Applications

  • Accent lighting
  • Industrial signage