MAX1553_15 Datasheet, PDF (7/10 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
Functional Diagram
V_CC
ENABLE
EN
CONTROL
CIRCUITRY
UVLO
1.25V
BANDGAP
REFERENCE
BIAS
GENERATOR
OV
OV
COMPARATOR
REF
LX
CONTROL
LOGIC
DRIVER
CURRENT
LIMIT
GND
V_LIM
REF
MINIMUM
t_OFF ONE-SHOT
MINIMUM
t_ON ONE-SHOT
ERROR
COMPARATOR
FB
MAX1553
MAX1554
128kΩ
67kΩ
96kΩ
110kΩ
BRT
1.25V
SS
2.7V TO 5.5V
INPUT
C1
4.7μF
ON
OFF
PWM
OR
DC CONTROL
C3
0.1μF
L1
47μH
D1
TOKO A920CY-470M ^CMDSH2-3
VCC
LX
EN
OV
MAX1553
C2
0.47μF
25V
R2
200kΩ
R3
10kΩ
C4
4700pF
D2–D7
WHITE
LEDs
BRT
FB
SS
GND
R1
10Ω
2.7V TO 5.5V
INPUT
C1
10μF
ON
OFF
PWM
OR
DC CONTROL
C3
0.1μF
L1
4.7μH
MURATA LQH32C
D1
CMDSH1-60M
VCC
LX
EN
OV
MAX1553
BRT
FB
SS
GND
C2
0.47μF
50V
R2
330kΩ
R3
10kΩ
C4
3300pF
R1
10Ω
D2–D10
WHITE
LEDs
Figure 1. Circuit with the MAX1553 Driving Six White LEDs
Figure 2. Circuit with the MAX1553 Driving Nine White LEDs at
Up to 15mA
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