ST1208
! Typical Operating Characteristics
Condition: VIN = VEN1 = VEN2 = 3.6 V, CIN = C1 = C2 = COUT = 1 uf, dropout current is 60 mA. ( 20 mA / LED X 3 ), LED
forward voltage Vf = 3.3 V, ISET = 125 uA
EFFICIENCY ( PLEDs / PBATT ) vs.
Li + BATTERY DISCHARGE
90
80
45mA
70
60
50
40
60mA
90mA
100mA
4.2 4.1 4.0 3.9 3.8 3.7 3.6 3.5 3.4
Li+ BATTERY VOLTAGE,
TIME-WEIGHTED ( V )
LED CURRENT vs. SUPPLY VOLTAGE
IIN ( mA )
Under-Voltage Protection
19
18
17
16
15
14
13
12
60
Increase
Reduce
50
40
30
20
10
LED1
LED2
LED3
0
2.1 2.32.5 2.72.9 3.13.3 3.53.7 3.94.1 4.34.5 4.74.9 5.15.3 5.5
SUPPLY VOLTAGE ( V )
VIN ( V )
2
2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3 3.1 3.2 3.3
ILED vs. ISET
50
40
30
20
10
0
VIN > 3.3 V
VIN = 3.0 V
VIN = 2.7 V
ILED = 30 mA @ Iset = 190
0
0
0
0
0
0
0
0
0
4
1
3
6
9
2
5
8
1
1
1
1
2
2
ISET ( uA )
VIN = 2.7 V
VIN = 3.6 V
VIN = 3.0 V
VIN = 4.2 V
VIN = 3.3 V
VIN = 5.0 V
V1.1
9/12
2004/10/27
SITRONIX [ SITRONIX TECHNOLOGY CO., LTD. ]
