MB3771
(2) 5 V Reference Voltage Generation and 5V Monitoring (No.1)
Detection Voltage = 4.2 V
In the above examples, the output voltage and the detection voltage are determined by the following equations:
Output Voltage = (R3 + R4) × VSC/R4
15 V
R5 : 3 kΩ
MB3771
8
7
6
5
1
2
3
4
RESET
CT
5 V( 50 mA)
0.47 µF
R3 : 3.6 kΩ
R4 : 1.2 kΩ
(3) 5 V Reference Voltage Generation and 5 V Monitoring (No. 2)
The value of R1 should be calculated from the current consumption of the MB3771, the current flowing at R2 and
R3, and the 5 V output current. The table below provides sample resistance values for reference.
VCC (V)
40
R1 (kΩ)
11
Output Current (mA)
< 1.6
< 1.4
< 0.6
24
6.2
15
4.7
VCC
R1
1
2
8
7
RESET
5 V
3
4
6
5
CT
R2 :
100 kΩ
0.47 µF
R3 : 33 kΩ
GND
(4) 1.245 V Reference Voltage Generation and 5 V Monitoring
Resistor R1 determines Reference current. Using 1.2 kΩ as R1, reference current is about 2 mA.
VCC
(5 V)
R1 : 10 kΩ
1
2
8
7
RESET
3
4
6
5
CT
Reference Voltage
1.245V typ.
0.47 µF
GND
12
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