MC34161, MC33161, NCV33161
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10
The above figure shows the MC34161 configured as a positive voltage window detector. This is accomplished by connecting channel 1 as an undervoltage detector
and channel 2 as an overvoltage detector. When the input voltage V
S
falls out of the window established by V
1
and V
4
, the LED will turn ‘ON’. As the input voltage
falls within the window, V
S
increasing from ground and exceeding V
2
, or V
S
decreasing from the peak towards ground and falling below V
3
, the LED will turn ‘OFF’
With the dashed line output connection, the LED will turn ‘ON’ when the input voltage V
S
is within the window.
For known resistor values, the voltage trip points are: For a specific trip voltage, the required resistor ratio is:
Figure 20. Positive Voltage Window Detector
V
1
+ (V
th1
* V
H1
)
ǒ
R
3
R
1
) R
2
) 1
Ǔ
V
3
+ (V
th2
* V
H2
)
ǒ
R
2
) R
3
R
1
) 1
Ǔ
V
2
+ V
th1
ǒ
R
3
R
1
) R
2
) 1
Ǔ
V
4
+ V
th2
ǒ
R
2
) R
3
R
1
) 1
Ǔ
R
2
R
1
+
V
3
(V
th2
* V
H2
)
V
1
(V
th1
* V
H1
)
* 1
R
3
R
1
+
V
3
(V
1
* V
th1
) V
H1
V
1
(V
th2
* V
H2
)
R
2
R
1
+
V
4
xV
th1
V
2
xV
th2
* 1
R
3
R
1
+
V
4
(V
2
* V
th1
)
V
2
xV
th2
+
1.27V
+
1.27V
+
2.8V
+
0.6V
+
-
2.54V
Reference
-
+
-
+
+
-
4
1
7
2
3
5
6
V
S
R
3
R
1
R
2
8
V
CC
Output
Voltage
Pins 5, 6
GND
CH2
CH1
LED `ON'
V
Hys2
V
Hys1
LED `ON'`OFF'LED `OFF'`ON'
V
4
V
3
V
2
V
1
V
CC
GND
Input V
S
The above figure shows the MC34161 configured as a negative voltage window detector. When the input voltage −V
S
falls out of the window established by V
1
and V
4
, the LED will turn ‘ON’. As the input voltage falls within the window, −V
S
increasing from ground and exceeding V
2
, or −V
S
decreasing from the peak towards
ground and falling below V
3
, the LED will turn ‘OFF’. With the dashed line output connection, the LED will turn ‘ON’ when the input voltage −V
S
is within the window
For known resistor values, the voltage trip points are: For a specific trip voltage, the required resistor ratio is:
Figure 21. Negative Voltage Window Detector
V
1
+
R
1
(V
th2
* V
ref
)
R
2
) R
3
) V
th2
V
2
+
R
1
(V
th2
* V
H2
* V
ref
)
R
2
) R
3
) V
th2
* V
H2
V
3
+
(R
1
) R
2
)(V
th1
* V
ref
)
R
3
) V
th1
V
4
+
(R
1
) R
2
)(V
th1
* V
H1
* V
ref
)
R
3
) V
th1
* V
H1
R
1
R
2
) R
3
+
V
1
* V
th2
V
th2
* V
ref
R
1
R
2
) R
3
+
V
2
* V
th2
) V
H2
V
th2
* V
H2
* V
ref
R
3
R
1
) R
2
+
V
th1
* V
ref
V
3
* V
th1
R
3
R
1
) R
2
+
V
th1
* V
H1
* V
ref
V
4
) V
H1
* V
th1
+
1.27V
+
1.27V
+
2.8V
+
0.6V
+
-
-
+
-
+
+
-
4
1
7
2
3
5
6
2.54V
Reference
R
3
R
1
R
2
-V
S
8
V
CC
Output
Voltage
Pins 5, 6
GND
CH2
CH1
V
1
V
2
V
3
V
4
V
CC
GND
Input -V
S
LED `ON' LED `ON'`OFF'LED `OFF'`ON'
V
Hys1
V
Hys2
