MAX1553_15 Datasheet, PDF (4/10 Pages) Maxim Integrated Products – High-Efficiency, 40V Step-Up Converters for 2 to 10 White LEDs

MAX1553/MAX1554
High-Efficiency, 40V Step-Up
Converters for 2 to 10 White LEDs
Typical Operating Characteristics
(MAX1553 driving six white LEDs, V_CC = V_EN = 3.6V, Circuit of Figure 1, T_A = +25°C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
DRIVING 6 WHITE LEDS
100
90
V_CC = 4V
V_CC = 5V
EFFICIENCY vs. LOAD CURRENT
DRIVING 6 WHITE LEDS
100
V_CC = 4V
V_CC = 5V
90
EFFICIENCY vs. LOAD CURRENT
DRIVING 6 WHITE LEDS
100
V_CC = 4V
V_CC = 5V
90
80
80
80
V_CC = 3.6V
V_CC = 3V
V_CC = 3.6V _{VCC = 3V}
70
V_CC = 3.6V
V_CC = 3V
70
70
60
L1 = 22μH
NO CAPACITOR ACROSS LEDs
50
0
5
10
15
20
LOAD CURRENT (mA)
EFFICIENCY vs. LOAD CURRENT
WITH MAX1554 DRIVING 9 WHITE LEDS
100
90
V_CC = 4V
V_CC = 5V
80
60
L1 = 33μH
4700pF ACROSS LEDs
50
0
5
10
15
20
LOAD CURRENT (mA)
LED CURRENT
vs. INPUT VOLTAGE
26
23 L1 = 22μH, NO CAPACITOR ACROSS LEDs
20
60
L1 = 47μH
4700pF ACROSS LEDs
50
0
5
10
15
20
LOAD CURRENT (mA)
LED CURRENT
vs. INPUT VOLTAGE
26
23
L1 = 22μH, NO CAPACITOR ACROSS LEDs
20
70
V_CC = 3.6V
60
CIRCUIT OF FIGURE 3
50
0
5
10
15
20
LOAD CURRENT (mA)
LED CURRENT vs. INPUT VOLTAGE
WITH MAX1554 DRIVING 9 LEDS
26
23
20
17
14
CIRCUIT OF FIGURE 3
11
3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
17
L1 = 47μH,
4700pF ACROSS LEDs
L1 = 33μH, 4700pF ACROSS LEDs
14
R1 = 10Ω, V_BRT = 1.25V
11
2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
LED CURRENT
vs. BRT VOLTAGE
35
30
25
20
15
10
5
0
0 0.6 1.2 1.8 2.4 3.0 3.6
BRT VOLTAGE (V)
17
L1 = 47μH,
4700pF ACROSS LEDs
L1 = 33μH, 4700pF ACROSS LEDs
14
R1 = 14Ω, V_BRT = 3.3V
11
2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
LED CURRENT
vs. BRT DUTY CYCLE
30
25
20
15
10
5
0
0
20
40
60
80
100
BRT DUTY CYCLE (%)
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