MC3423
*
F1
(+ Sense
Lead)
R1
1
Power
Supply
2
8
3 MC3423
RG
R2
4 75
(− Sense Lead)
+
To
Load
S1*
−
ǒ Ǔ ǒ Ǔ Vtrip + Vref
1
)
R1
R2
[ 2.6 V
1
)
R1
R2
R2 ≤ 10 kW for minimum drift
For minimum value of RG, see Figure 9.
*See text for explanation.
Figure 4. Basic Circuit Configuration
Power
Supply
RS
1N4740
10V
+ 10mF
15V
(+ Sense
Lead)
R1
1
8
MC3423
2
3
4
*R2
7 5 (− Sense
Lead)
+
Q1
To
Load
VS
C1
−
C1 >
RS
R1R2
(R1 + R2) 10mF
ǒ Ǔ RS +
VS – 10
25
kW
ǒ Ǔ ǒ Vtrip + Vref
1
)
R1
R2
[ 2.6 V
1
)
R
R
*R2 ≤ 10 kW
Q1: VS ≤ 50 V; 2N6504 or equivalent
Q1: VS ≤ 100 V; 2N6505 or equivalent
Q1: VS ≤ 200 V; 2N6506 or equivalent
Q1: VS ≤ 400 V; 2N6507 or equivalent
Q1: VS ≤ 600 V; 2N6508 or equivalent
Q1: VS ≤ 800 V; 2N6509 or equivalent
Figure 5. Circuit Configuration for Supply Voltage Above 36 V
Power
Supply
R1
2
R2
16
MC3423
R3
V10
Indication
8 Out
RG
4 3 57
VO
VC
C
R3
≥
Vtrip
10 mA
+VCC
VCC
Vtrip
0
VC
Vref
0
VO
0
td
VIO
td =
Vref
Isource
× C ≈ [12 × 103] C
Figure 6. Basic Configuration for Programmable Duration
of Overvoltage Condition Before Trip
(See Figure 10)
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