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MB3773 Datasheet, PDF (17/31 Pages) Fujitsu Component Limited. – Power Supply Monitor with Watch-Dog Timer | |||
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MB3773
EXAMPLE 5: Monitoring Two Supply Voltages (with hysteresis and reset output)
VCC2 (12
VCC1 (5 V)
CT
MB3773
1
8
2
7
3
6
4
5
1.2 kâ¦
R1
20 kâ¦
R6
30 kâ¦
R3
Diode
180 kâ¦
R4
+
_
Comp. 1
+
_
Comp. 2
5.1 kâ¦
R2
4.7 kâ¦
R5
Logic circuit
RESET
RESET
CK
GND
Example : Comp. 1, Comp. 2
: MB4204, MB47393
Notes :
⢠When either 5 V or 12 V supply voltage decreases below its detection voltage (VSL), the MB3773 RESET terminal
is set to High and the MB3773 RESET terminal is set to Low.
⢠Use VCC1 ( = 5 V) to power the comparators (Comp. 1 and Comp. 2) in the external circuit shown above.
⢠The detection voltage of the VCC2 ( = 12 V) supply voltage is approximately 9.2 V/9.4 V and has a hysteresis width
of approximately 0.2 V. For the formulas for finding hysteresis width and detection voltage, refer to section 4.
Document Number: 002-08513 Rev. *A
Page 17 of 31
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