Diodes AL8805 - Manual (Page 5)

AL8805
Document number: DS35030 Rev. 4 - 2
5 of 16
www.diodes.com
July 2012
© Diodes Incorporated
AL8805
Typical Performance Characteristics
(cont.) (@T
A
= +25°C, unless otherwise specified.)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0% 20% 40% 60% 80% 100%
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
L
E
D CURREN
T
(
A
)
PWM DUTY CYCLE
Figure 7 I vs. PWM Duty Cycle
LED
LE
D
C
U
R
R
EN
T
E
R
R
O
R
(%
)
0
60
120
180
240
300
6 12 18 24 30 36
V (V)
Figure 8 SW R vs. Input Voltage
IN
DS(ON)
R
(m
)
DS
(O
N)
Ω
V = Open
V = V
T = 25 C
CTRL
SET IN
A
°
100
150
200
250
300
350
400
-40 -15 10 35 60 85 110
AMBIENT TEMPERATURE (°C)
Figure 9 SW R vs. Temperature
DS(ON)
R(
m
)
DS
(O
N)
Ω
80
85
90
95
100
105
110
115
120
125
130
-2
0
2
4
6
8
10
12
14
16
18
TIME (µs)
Figure 10 SW Output Switching Characteristics
V
SW
V(
m
V
)
SEN
S
E
R = 150m
L = 68µH
V = 12V
1 LED Load
SET
IN
Ω
V
SW
V
SENSE
I
LED
V
SW
V
CTRL
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 50 100 150 200
Time (µs)
Figure 11 PWM Dimming
0
2
4
6
8
10
12
14
16
18
20
Duty Cycle = 5%
SW
IT
C
H
a
n
d
C
T
RL
V
O
L
T
AG
E (
V
)
L
E
D CURREN
T
(
A
)
R = 150m , L =68µH, V = 12V, 1LED Load, T =25 C
SET IN A
Ω °
6 9 12 15 18 21 24 27 30
INPUT VOLTAGE (V)
Figure 12 Duty Cycle vs. Input Voltage
D
U
T
Y
C
Y
C
LE
L = 33µH
R = 150m
T = 25°C
2 LED
S
A
Ω
33 36