L1937 Datasheet, PDF (3/7 Pages) Unisonic Technologies – WHITE LED STEP-UP CONVERTER

UTC L1937
TYPICAL APPLICATIONS
LINEAR INTEGRATED CIRCUIT
VIN
3V ~ 5V
OFF ON
C1
1DŽF
L1
22DŽF
D1
VIN
SW
SHDN FB
GND
LED 1
LED 2
LED 3
C2
0.22DŽF
15mA
R1
6.34Ƹ
Li-Ion Powered Driver for Three White LEDs
Conversion Efficiency
90
85
80
VIN=3V
75
VIN=3.6V
70
65
60
0
5
10
15
LED CURRENT (mA)
20


86
VIN
3V ~ 5V
CIN
1DŽF
L
22DŽH
D
VDC
DIMMING
VIN
SW
84
COUT
82
1DŽF
80
90k
78
5k
SHDN FB
GND
R1
2Ƹ
76
74
72
Li-Ion to Two White LEDs
70
0
Two LED Efficiency
VIN=3.6V
VIN=3V
10
20
30
LED CURRENT (mA)
40


UTC UNISONIC TECHNOLOGIES CO., LTD. 3
QW-R103-021,A