NJM2078
3. Detection of Abnormal Operating Voltage
4. Programmable Zener
V+H
=
1 +
R3
R4
VR
V
+
L
=
1 +
R1
R2
VR
Note : V+L≥2.5V
VZ・=・ 1
+
R2
R3
VR
Vz ≤V V + − Vz ≤6mA
R2 + R3
R1
Can use channel B independently.
5. Reset Circuit for Decreased Operating Voltage
Comparate Voltage and hysterisis width can be
adjustabel by R1 to R4. Roughly.
V +(L)
=
R1
+ R2
R3
+ R3
VTH
V
+
(H)
=
V
+
(L)
R1(R2 + R3 )
R 3R 4
VTH
● Power-on reset time tRST (roughly)
tRST = -C1R4 In
1 −
VTH
V+
1 +
R1
R2 + R3
● Transistor ; Recommended hFE = 50 to 200
● Rapid Signal Off ; Be care to remained charge
of C1. It affects to tRST
● Reverse polarity output OUT : Open collector.
-6-
Ver.2003-12-09