NCP1117, NCV1117
Constant Current
Output
Input
NCP1117
XTA
3
2
Output
Input
R
+
+
NCP1117
XTA
3
2
10
mF
10
mF
R1
1
+
+
50 k 1N4001
10
mF
10
mF
1
R2
2N2907
10
mF
V
R
ref
I
+
) I
out
adj
Figure 24. Constant Current Regulator
Figure 25. Slow Turn−On Regulator
Output
Input
NCP1117
XTA
3
2
+
+
10
mF
10
mF
R1
R2
1
Output
Input
NCP1117
XTA
3
2
+
+
10
10
mF
120
360
1
mF
2N2222
1.0 k
Output Control
On
2N2222
1.0 k
Off
Output Voltage Control
Resistor R2 sets the maximum output voltage. Each
transistor reduces the output voltage when turned on.
V
+ V
ref
out(Off)
Figure 26. Regulator with Shutdown
Figure 27. Digitally Controlled Regulator
Output
Input
3
NCP1117
XT50
2
+
+
10
10
1
mF
mF
50 W
Input
Output
5.0 V to
12 V
+
3
2
NCP1117
XT50
5.3 V AC Line
5.0 V Battery
R
CHG
+
10
mF
10
mF
1
NCP1117
XT50
3
2
+
+
10
10
+
6.6 V
2.0 k
1
mF
mF
−
The 50 W resistor that is in series with the ground pin of the
upper regulator level shifts its output 300 mV higher than the
lower regulator. This keeps the lower regulator off until the
input source is removed.
Figure 28. Battery Backed−Up Power Supply
Figure 29. Adjusting Output of Fixed
Voltage Regulators
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