LM3444A9 Datasheet, PDF (1/10 Pages) National Semiconductor (TI) – Edison Retrofit Evaluation Board included in this shipment converts

LM3444 A19 Edison Retrofit
National Semiconductor
Application Note 2083
Evaluation Board
Clinton Jensen
December 2, 2010
Introduction
The evaluation board included in this shipment converts
85V_AC to 135V_AC input and drives five to thirteen series con-
nected LED’s at the currents listed in the Evaluation Board
Operating Conditions section. 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 stan-
dard A19 Edison socket. Output current is regulated within
±15% of nominal from circuit to circuit and over line voltage
variation. Refer to the LM3444 datasheet 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 character-
istics including EMI/EMC data. The above restrictions for the
Simplified LM3444 Schematic
input voltage are valid only for the demonstration board as
shipped with the schematic below. Please refer to the LM3444
data sheet for detailed information regarding the LM3444 de-
vice. 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.
Evalution Board Operating
Conditions
V_IN = 85V_AC to 135V_AC
5 to 13 series connected LEDs as configured with the currents
listed below
Can drive up to 18 series LEDs (see table)
I_LED = 340 mA (5 LEDs)
I_LED = 300 mA (7 LEDs)
I_LED = 260 mA (9 LEDs)
I_LED = 230 mA (11 LEDs)
I_LED = 205 mA (13 LEDs)
30131201
Warning: The LM3444 evaluation boards have no isolation or any type of protection from shock. Caution must be taken when handling evaluation board.
Avoid touching evaluation board, and removing any cables while evaluation board is operating. Isolating the evaluation board rather than the
oscilloscope is highly recommended.
Warning: This LM3444 evaluation PCB is a non-isolated design. The ground connection on the evaluation board is NOT referenced to earth ground. If an
oscilloscope ground lead is connected to the evaluation board ground test point for analysis, and AC power is applied, the fuse (F1) will fail open.
The oscilloscope should be powered via an isolation transformer before an oscilloscope ground lead is connected to the evaluation board.
© 2010 National Semiconductor Corporation 301312
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