LM3444-EDSNEV/NOPB

1 Introduction

The evaluation board included in this shipment converts 85VAC to 135VAC input and drives five to thirteen series connected LED’s at the currents listed in Section 2. This is a two-layer board using the bottom and top layer for component placement. The board is surrounded by a larger area allowing for extra test points and connectors for ease of evaluation. The actual board size is contained inside the larger outer area and can be cut out for the smallest size possible. The evaluation board can be modified to adjust the LED forward current and the number of series connected LEDs. The topology used for this evaluation board eliminates the need for passive power factor correction and results in high efficiency and power factor with minimal component count which results in a size that can fit in a standard A19 Edison socket. Output current is regulated within ±15% of nominal from circuit to circuit and over line voltage variation. Refer to the LM3444 AC-DC Offline LED Driver (SNVS682) data sheet for details on the LM3444 IC.

A bill of materials below describes the parts used on this demonstration board. A schematic and layout have also been included below along with measured performance characteristics including EMI/EMC data. The above restrictions for the input voltage are valid only for the demonstration board as shipped with the schematic below. The board is currently set up to drive five to thirteen series connected LEDs, but the evaluation board may be modified to accept more series LEDs. Refer to the tables in this document for modifying the board to accept more LEDs and/or adjust for different current levels.

Evaluation Board Operating Conditions

VIN = 85VAC to 135VAC

5 to 13 series connected LEDs as configured with the currents listed below

Can drive up to 18 series LEDs (see table) ILED = 340 mA (5 LEDs)

ILED = 300 mA (7 LEDs)

ILED = 260 mA (9 LEDs)

ILED = 230 mA (11 LEDs)

ILED = 205 mA (13 LEDs)

3 Simplified LM3444 Schematic