AL8808 Datasheet, PDF (4/20 Pages) Diodes Incorporated – COST EFFECTIVE LOW EMI 30V 1A BUCK LED DRIVER

AL8808
Typical Performance Characteristics (@ T_A = +25°C, unless otherwise stated.)
400
350
300
250
200
150
100
50
V_CTRL = 0V
V_SET = V_IN
T_A = +25°C
0
0 3 6 9 12 15 18 21 24 27 30
INPUT VOLTAGE (V)
Figure 2. Supply Current vs. Input Voltage
1.2
T_A = +25°C
1.0
V_IN = 12V
L = 68µH
1 LED
R_SET = 100mΩ
0.8
R_SET = 150mΩ
0.6
0.4
R_SET = 300mΩ
0.2
900
800
L = 33µH
700
600
T_A = +25°C
V_IN = 12V
R_SET = 150mΩ
1 LED
500
400
L = 68µH
300
200
100
L = 100µH
0
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
20
T_A = +25°C, V_IN = 12V
0 ^{L = 68µH, R}SET ^{= 150mΩ}
1 LED
-20
-40
-60
-80
-100
0.0
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
6
0.9
T_A = +25°C, V_IN = 12V
L = 68µH, R_SET = 150mΩ
5
1 LED, f_PWM = 500Hz
4
0.6
3
2
0.3
1
0
0.0
0
20
40
60
80
100
PWM DUTY CYCLE (%)
Figure 6. I_LED vs. PWM Duty Cycle
-120
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_CTRL vs. V_CTRL
100
90
80
70
60
50
40
30
20
10
T_A = +25°C, R_SET = 150mΩ
L = 33µH, L = 68µH, L = 100µH
0
6 9 12 15 18 21 24 27 30
INPUT VOLTAGE V_CTRL (V)
Figure 7. Duty Cycle vs. Input Voltage
AL8808
Document number: DS35648 Rev. 2 - 2
4 of 20
www.diodes.com
January 2013
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