Datasheet

-50 -30 -10 10 30 50 70 90 110130150
1.25
1.26
1.27
1.28
1.29
V
OFF
(V)
TEMPERATURE (°C)
OFF Threshold at C11
V
BUCK
(V)
NORMALIZED SW FREQ
1.50
1.25
1.00
0.75
0.50
0.25
0 50 100 150 200
3 LEDs
5 LEDs
7 LEDs
9 LEDs
Series
connected LEDs
UVLO
(V)
8.0
7.5
7.0
6.5
6.0
-50 -25 0 25 50 75 100 125 150
UVLO (V
CC
) Rising
UVLO (V
CC
) Falling
TEMPERATURE (°C)
200.0
190.0
180.0
170.0
160.0
150.0
-50 -25 0 25 50 75 100 125 150
TEMPERATURE (°C)
t
ON-MIN
(ns)
LINE VOLTAGE (V
AC
)
f
SW
(Hz)
300k
250k
200k
150k
100k
50k
0
80 90 100 110 120 130 140
C11 = 2.2 nF, R3 = 348 k:
7 LEDs in Series (V
O
= 24.5V)
LINE VOLTAGE (V
AC
)
EFFICIENCY (%)
95.0
90.0
85.0
80.0
75.0
80 90 100 110 120 130 140
14 Series connected LEDs
10 Series connected LEDs
LM3444
www.ti.com SNVS682C –NOVEMBER 2010–REVISED MAY 2013
TYPICAL PERFORMANCE CHARACTERISTICS
f
SW
vs Input Line Voltage Efficiency vs Input Line Voltage
Figure 3. Figure 4.
V UVLO
CC
vs Temperature Min On-Time (t
ON
) vs Temperature
Figure 5. Figure 6.
Off Threshold (C11) vs Temperature Normalized Variation in f
SW
over V
BUCK
Voltage
Figure 7. Figure 8.
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