MB3773
EXAMPLE 5 : Montitoring Two (M) Supply Voltages (with hysterisis and reset output)
VCC2 (12V)
VCC1 (5V)
20k
R6
MB3773
Logic circuit
1
2
3
4
8
7
6
5
RESET
RESET
CK
Diode
CT
30k
R3
GND
180k
R4
+
_
+
_
Comp. 1
1.2k
R1
Comp. 2
5.1k
R2
4.7k
R5
Example
: Comp. 1, Comp. 2
: MB4204, MB47393
SL), the MB3773
NOTE: When either 5V or 12V supply voltage decreases below its detection voltage (V
RESET pin is set to High and the MB3773 RESET pin is set to Low.
• Use VCC1 (=5V) to power the comparators (Comp. 1 and Comp. 2) in the external circuit shown
above.
• The detection voltage of the VCC2 (=12V) supply voltage is approximately 9.2V/9.4V and has a
hysterisis width of approximately 0.2V.
For the formulas for finding hysterisis width and detection voltage, see section 4.
13
FUJITSU [ FUJITSU ]
