R3115Z

8

OPERATION

Current

Source

Rd

Rb

Rc

Vref

Tr.1

Tr.2

Nch

Pch

OUT

GND

Schmitt Trigger

Comparator

Ra

Fig. 1 Block Diagram with an external capacitor

Released Voltage

Detector Threshold

1

2

3

4

5

Minimum Operating

GND

Output Voltage(OUT)

GND

A

B

HYSTERESIS

RANGE

Delay

Time

Voltage

Operation Status

1

2

3

4

5

Input Voltage

Compartor Output

L

H Indefinite ON OFF

Tr.1,2

OFF ON Indefinite ON OFF

Nch OFF ON Indefinite ON OFF

Output

Tr.

Pch

ON OFF Indefinite OFF ON

Rb

+Rc

Ra

+Rb+Rc

Rb

Ra

+Rb

Fig. 2 Operation Diagram

1. Output voltage is equal to supply voltage. (As for Nch open drain type, equal to pull-up voltage.)

2. When the supply voltage is down to the detector threshold voltage level(Point A),

output voltage becomes GND level.

3. When the supply voltage is lower than minimum operating voltage, the operation of output transistor is

indefinite. In the case of Nch open drain type, output voltage is equal to pull-up voltage.

4. Output Voltage becomes GND level.

output of the comparator reaches the threshold level, and Output of Shmitt Trigger is reversed from “H” to

“L”, then output voltage is equal to supply voltage. (As for Nch open drain type, equal to pull-up voltage.)

∗) The difference between released voltage and detector threshold voltage means hysteresis range voltage.