MC34161, MC33161, NCV33161

http://onsemi.com

11

The above figure shows the MC34161 configured as a positive and negative overvoltage detector. As the input voltage increases from ground, the LED will turn

For known resistor values, the voltage trip points are:

For a specific trip voltage, the required resistor ratio is:

Figure 22. Positive and Negative Overvoltage Detector

V

R

3

R

4

(V

V

R

3

R

4

(V

V

R

2

R

1

) 1

V

R

2

R

1

) 1

R

3

R

4

+

(V

(V

R

3

R

4

+

(V

(V

R

2

R

1

+

V

4

V

th2

* 1

R

2

R

1

+

V

3

V

* 1

+

1.27V

+

1.27V

+

2.8V

+

0.6V

+

−

2.54V

Reference

−

+

−

+

+

−

4

1

7

2

3

5

6

R2

8

Output

Voltage

Pins 5, 6

GND

LED ‘ON’

GND

The above figure shows the MC34161 configured as a positive and negative undervoltage detector. As the input voltage decreases toward ground, the LED will

For known resistor values, the voltage trip points are:

For a specific trip voltage, the required resistor ratio is:

Figure 23. Positive and Negative Undervoltage Detector

V

R

4

R

3

) 1

V

R

4

R

3

) 1

V

R

1

R

2

(V

V

R

1

R

2

(V

R

4

R

3

+

V

2

V

th1

* 1

R

4

R

3

+

V

1

V

* 1

R

1

R

2

+

V

V

R

1

R

2

+

V

V

+

1.27V

+

1.27V

+

2.8V

+

0.6V

+

−

−

+

−

+

+

−

4

1

7

2

3

5

6

2.54V

Reference

8

GND

GND

Output

Voltage

Pins 5, 6

LED ‘ON’