LM3445_1 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – 230VAC, 6W- 15W Isolated Flyback LED Driver Solid State Lighting

LM3445 - 230VAC, 6W- 15W National Semiconductor
Application Note 2069
Isolated Flyback LED Driver Montu Doshi
November 23, 2010
Introduction
This demonstration board highlights the performance of a
LM3445 based Flyback LED driver solution that can be used
to power a single LED string consisting of 4 to 10 series con-
nected LEDs from an 180 V_RMS to 265 V_RMS, 50 Hz input
power supply. The key performance characteristics under
typical operating conditions are summarized in this applica-
tion note.
This is a four-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 LM3445 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
• Drop-in compatibility with TRIAC dimmers
• Line injection circuitry enables PFC values greater than
0.94
• Adjustable LED current and switching frequency
• Flicker free operation
Applications
• Retro-fit TRIAC Dimming
• Solid State Lighting
• Industrial and Commercial Lighting
• Residential Lighting
Performance Specifications
Based on an LED V_f = 3.4V
Symbol
Parameter
V_IN
V_OUT
I_LED
P_OUT
f_sw
Input voltage
LED string voltage
LED string average current
Output power
Switching frequency
Min
180 V_RMS
13 V
-
-
-
Typ
230 V_RMS
20 V
350 mA
7.2 W
67 kHz
Max
265 V_RMS
27 V
-
-
-
Demo Board
Dimming Characteristics
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30126924
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