77

●Circuit operation

(1) The basic application examples are shown in Fig.2.

  The externally installed parts are only the input and

output smoothing capacitors.

(2) Switching on and off the output voltage is allowed.

 

The output can be switched off by making pin 4 to

be open (high impedance). (See Fig.3)

(3) Fine adjustment of the output voltage is allowed.

The fine adjustment of output voltage can be

performed from pin 6 via the resistor by connecting

the output terminal (pin 2) or GND.(See

application example3)

●Application example

Application example 1 : DC / DC converter with a protection circuit

Fig.3

470

µF

120pF

100

µF

0.22

Ω

COMP.

2.2M

Ω※

＋

−

BA10393

24V

5V

9

7 6 5 4 3 2 1

BP5220A / BP5221A / BP5222A

＋

＋

Fig.4

0.2

0.4

0.6

0.8

1.0

1.2

6

5

4

3

2

1

0

OUTPUT CURRENT（A）

Fig.5

Fig.6

※A resistor to secure the rise of output at power on. The resistance to be selected depends on the input voltage.

This is a standard application. Because the control current fluctuates with variations in circuits and components,

set the control current by adding a sufficient margin to the normal current level.

9

7

6

5

4

3

2

1

470

µF

BP5220A / BP5221A / BP5222A

100

µF

＋

＋

Fig.2

Be sure to use fuse

for safety.

9

7

6

5

4

3

2

1

470

µF

SW

BP5220A / BP5221A / BP5222A

Output OFF

＋

100

µF

＋

Be sure to use fuse

for safety.

Application example 2 : Output ON / OFF control

9

7

6

5

4

3

2

1

470

µF

100k

Ω

2SC1740

BP5220A / BP5221A / BP5222A

ON / OFF

100

µF

＋

＋

Be sure to use fuse

for safety.