M51995AP/AFP

REJ03D0835-0300 Rev.3.00 Jun 06, 2008

Page 25 of 40

≈ 7.1 V

F/B

DET

2.5 V

500

Ω

6 S

3 k

1 S

+

−

OP

AMP

Figure 16 Equivalent Circuit Diagram of Voltage Detector

ON-OFF Circuit Section

Figure 17 shows the circuit diagram of ON-OFF circuit. The current flown into the ON-OFF terminal makes the Q4

“on” and the switching operation stop. On the other hand, the switching operation will recover as no current flown into

ON/OFF terminal makes Q4 “off”. As the constant current source connected to Q4 base terminal has such the

hysteresis characteristics of 20

µA at operation and 3 µA at stopping. So the unstable operation is not appeared even if

the ON/OFF terminal voltage signal varies slowly.

Q4

Q3

Q2

Q1

2 k

I

ON/OFF

Operate stop at Q4 ON

I: 3

µA at stopping

I: 20

µA at operating

Figure 17 ON/OFF Circuit

Figure 18 shows how to connect the ON/OFF terminal. The switching operation will stop by switch-off and operate by

switch-on.

Transistor or photo transistor can be replaced by this switch, of course. No resistor of 30 to 100 k

Ω is connected and

ON/OFF terminal is directly connected to GND, when it is not necessary to use the ON/OFF operation.

adequate voltage, when R1 shown in Application Example is selected properly.