Diodes AL8808 - Manual (Page 4)

AL8808
Document number: DS35648 Rev. 2 - 2
4 of 20
www.diodes.com
January 2013
© Diodes Incorporated
NEW PROD
UC
T
AL8808
Typical Performance Characteristics
(@ T
A
= +25°C, unless otherwise stated.)
0 3 6 9 12 15 18 21 24 27 30
INPUT VOLTAGE (V)
Figure 2. Supply Current vs. Input Voltage
400
350
300
250
200
150
100
50
0
IN
P
U
T
C
U
R
R
EN
T
(µ
A
)
V = 0V
V = V
T = +25°C
CTRL
SET
IN
A
L = 33µH T = +25°C
V = 12V
R
= 150m
1 LED
A
IN
SET
Ω
L = 68µH
L = 100µH
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
V
CTRL
(V)
Figure 3. Switching Frequency vs. V
CTRL
900
800
700
600
500
400
300
100
0
F
R
E
Q
U
E
N
C
Y
(k
H
z)
200
T = +25°C
V
= 12V
L = 68µH
A
IN
1 LED
R
SET
= 100m Ω
R
SET
= 150m Ω
R
SET
= 300m Ω
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
V
CTRL
(V)
Figure 4. LED Current vs. V
CTRL
1.2
1.0
0.8
0.6
0.4
0.2
0.0
LE
D
C
U
R
R
EN
T
(A
)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
V
CTRL
(V)
Figure 5. I vs. V
CTRL CTRL
20
0
-20
-40
-60
-80
-100
-120
C
T
R
L
P
IN
C
U
R
R
E
N
T
(µ
A
)
T = +25°C, V = 12V
L = 68µH, R
A IN
SET
= 150m
1 LED
Ω
0 20 40 60 80 100
PWM DUTY CYCLE (%)
Figure 6. I vs. PWM Duty Cycle
LED
6
5
4
3
2
1
0
LE
D
C
U
R
R
EN
T
E
R
R
O
R
(%
)
0.9
LE
D
C
U
R
R
EN
T
(A
)
0.6
0.3
0.0
T = +25°C, V = 12V
L = 68µH, R
A IN
SET
PWM
= 150m
1 LED, f = 500Hz
Ω
6 9 12 15 18 21 24 27 30
INPUT VOLTAGE V
CTRL
(V)
Figure 7. Duty Cycle vs. Input Voltage
100
90
70
60
40
30
10
0
D
U
T
Y
C
Y
C
LE
(
%
)
80
50
20
T = +25°C, R = 150m
L = 33µH, L = 68µH, L = 100µH
A SET
Ω