LP2950
TYPICAL APPLICATIONS
Figure 18. Lithium Ion Battery Cell Charger
Figure 19. Low Drift Current Sink
+V = 2.0 to 30 V
Unregulated Input
6.0 to 10 Vdc
I
L
I = 1.23/R
L
Load
8
V
1N4001
330 pF
4.2 V ± 0.025 V
in
1
2
5
Error
V
out
NC
8
0.1 µF
2.0 M
1.0%
NC
NC
SNS
LP2951CN
V
in
1
2
Error
Output
5
V
0.1 µF
Error
out
3
6
SD
V T
O
SNS
LP2951CN
806 k
1.0%
Lithium Ion
Rechargeable
Cell
Gnd FB
2.2 µF
Shutdown
Input
3
6
4
7
SD
V T
O
50 k
Gnd FB
4
7
Gnd
1.0 µF
R
Figure 20. Latch Off When Error Flag Occurs
Figure 21. 5.0 V Regulator with 2.5 V Sleep Function
+V
in
+V
in
CMOS
Gate
*Sleep
Input
8
V
in
470 k
470 k
470 k
8
V
in
47 k
Error
1
2
5
3
V
V
out
Error
out
V
out
2N3906
2N3906
1
2
5
V
out
Error
Output
NC
NC
SNS
LP2951CN
Reset
NC
NC
SNS
LP2951CN
200 k
100 k
6
R1
R2
SD V T
O
Shutdown
Input
3
6
3.3 µF
Normally
Closed
SD
V T
O
Gnd FB
1.0 µF
100 pF
4
7
Gnd FB
4
7
100 k
Error flag occurs when V is too low to
in
maintain V , or if V
out out
excessive load current.
is reduced by
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