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