W-6137 Datasheet, PDF (11/16 Pages) Copal Electronics – CMOS Boost Converter

W-6137
Typical Applications
V_IN
L
D
2.2 V to
5.0 V
33 H
C1
SW
1F
VIN
V_OUT
C2
1F
OFF _ON
W-6137
SHDN FB
GND
V_FB = 300 mV
20 mA
R1
15
L: Sumida CDRH3D16ï330
D: Central CMDSH2-3 (rated 30 V)
C2: Taiyo Yuden GMK212BJ105KG-T (rated 35 V)
Figure 25. W-6137 Driving Two LEDs
For best performance, a 33 H inductor and a 1 F output
capacitor are recommended for 2ïLED applications.
In ï/(' configuration, the W-6137 can be powered
from two AA alkaline cells or from a Liïion 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
11