PT6937 Datasheet, PDF (8/15 Pages) Princeton Technology Corp – White LED Step-Up Converter

White LED Step-Up Converter
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URL: http://www.princeton.com.tw
PT6937
TYPICAL APPLICATIONS
VIN
3V ~ 5V
OFF ON
L1
22 H
D1
C1
1F
VIN
LED 1
SW _{LED 2}
PT6937 ^{LED 3}
/SHDN FB
GND
15mA
R1
6.43
C2
0.22 F
PTC PT6937 (3 LEDs)
90%
80%
70%
60%
50%
2
5 10 15 20
D1: FAIRCHILD 1N5819
L1: 3L Electronic Corp. SMTSDR322520C-220K
LED CURRENT (mA )
Li-Ion Powered Driver for Three White LEDs
VIN
3V ~ 5V
CIN
1F
L1
22 H
D1
VDC
DIMMING
VIN
SW
90K
PT6937
5K
/SHDN FB
GND
R1
2.2
D1: FAIRCHILD 1N5819
L1: 3L Electronic Corp. SMTSDR322520C-220K
COUT
1F
PTC PT6937 (2 LEDs)
85%
80%
75%
70%
65%
60%
55%
50%
2 5 10 15 20
LED CURRENT (mA)
V IN = 3V
V IN = 3.6V
VIN = 3V
VIN = 3.6V
VIN
3V ~ 5V
Li-Ion to Two White LEDs
L1
22 H
D1
CIN
1F
VDC
DIMMING
VIN
SW
90K
PT6937
5K
/SHDN FB
GND
R1
4.75
D1: FAIRCHILD 1N5819
L1: 3L Electronic Corp. SMTSDR322520C-220K
COUT
0.22 F
90%
80%
70%
60%
50%
PTC PT6937 (3 LEDs)
2 5 10 15 20
LED CURRENT (mA)
Li-Ion to Three White LEDs
VIN = 3V
VIN = 3.6V
PT6937 V1.1
-8-
March, 2006