LM3444 - 120VAC, 8W Isolated Flyback LED Driver
LM3444 -120VAC, 8W
Isolated Flyback LED Driver
National Semiconductor
Application Note 2082
Clinton Jensen
December 7, 2010
Introduction
This demonstration board highlights the performance of a
LM3444 based Flyback LED driver solution that can be used
to power a single LED string consisting of 4 to 8 series con-
nected LEDs from an 90 V
RMS
to 135 V
RMS
, 60 Hz input power
supply. The key performance characteristics under typical
operating conditions are summarized in this application note.
This is a two-layer board using the bottom and top layer for
component placement. The demonstration board can be
modified to adjust the LED forward current, the number of se-
ries connected LEDs that are driven and the switching fre-
quency. Refer to the LM3444 datasheet for detailed instruc-
tions.
A bill of materials is included that describes the parts used on
this demonstration board. A schematic and layout have also
been included along with measured performance character-
istics.
Key Features
•
•
•
Line injection circuitry enables PFC values greater than
0.99
Adjustable LED current and switching frequency
Flicker free operation
Applications
•
•
•
Solid State Lighting
Industrial and Commercial Lighting
Residential Lighting
Performance Specifications
Based on an LED V
f
= 3.57V
Symbol
V
IN
V
OUT
I
LED
P
OUT
f
sw
Parameter
Input voltage
LED string voltage
LED string average current
Output power
Switching frequency
Min
90 V
RMS
12 V
-
-
-
Demo Board
Typ
120 V
RMS
21.4 V
350 mA
7.6 W
79 kHz
Max
135 V
RMS
30 V
-
-
-
30131168
AN-2082
© 2010 National Semiconductor Corporation
301311
www.national.com
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