M51995AP/AFP

REJ03D0835-0201 Rev.2.01 Nov 14, 2007

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.

Figure 19 shows the ICC versus VCC characteristics in OFF state and VCC will be kept at not so high or low but at the

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