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POWER-FAIL COMPARATOR Figure 6
V
CC
GND
PFO
PFI
+5V
C1
R1
VIN
R2
R3
to µP
TRIP
= 1.25
H
= 1.25 /
R2||R3
R1 + R2||R3
R1 + R2
I
– 1.25
+
5 - 1.25
=
1.25