CAT4137 Datasheet, PDF (10/16 Pages) Catalyst Semiconductor – CMOS Boost Converter - White LED Driver

TYPICAL APPLICATIONS
CAT4137 Driving Two LEDs
V_IN
2.2V to
5.0V
C1
1µF
OFF ON
L
33µH
D
V_OUT
C2
SW
VIN
1µF
CAT4137
SHDN
V_FB = 300mV
FB
GND
20mA
R1
15Ω
L: Sumida CDRH3D16-330
D: Central CMDSH2-3 (rated 30V)
C2: Taiyo Yuden GMK212BJ105KG-T (rated 35V)
For best performance, a 33µH inductor and a 1µF
output capacitor are recommended for 2-LED
applications.
In 2-LED configuration, the CAT4137 can be powered
from two AA alkaline cells or from a Li-ion battery.
CAT4137
Efficiency vs. LED Current, Two LEDs
100
95
VIN = 3.6V
90
85
80
VIN = 3V
75
70
0
10
20
30
40
LED CURRENT [mA]
Doc. No. MD-5012 Rev. B
10
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice