CAT4137 Datasheet, PDF (11/16 Pages) Catalyst Semiconductor – CMOS Boost Converter - White LED Driver

CAT4137
Typical Applications
V_IN
L
D
2.2 V to
5.0 V
33 mH
C1
1 mF
SW
VIN
V_OUT
C2
1 mF
OFF _ON
CAT4137
SHDN FB
GND
V_FB = 300 mV
20 mA
R1
15 W
L: Sumida CDRH3D16−330
D: Central CMDSH2-3 (rated 30 V)
C2: Taiyo Yuden GMK212BJ105KG-T (rated 35 V)
Figure 25. CAT4137 Driving Two LEDs
For best performance, a 33 mH inductor and a 1 mF 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.
100
95
90
VIN = 3.6 V
85
VIN = 3.0 V
80
75
70
0
10
20
30
40
LED CURRENT (mA)
Figure 26. Efficiency vs. LED Current, Two LEDs
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