S1F76640 Series

Parallel Connection

It is possible to make the output impedance RO small when several pieces of the circuit shown in Figure 8.1 are connected. Parallel connection of n circuits reduces RO to 1/n approximately. One piece of the smoothing capacitor C4 can be commonly used in the same way. To get stabilized outputs after parallel connection, include 1 pieces of the circuit shown in Figure 8.2 in the parallel connection of n circuits as shown in Figure 8.3.

VREG

1

RV

VRI

16

 

 

 

1

RV

VRI 16

 

 

2

VREG

VO

15

 

 

 

2

VREG

VO 15

 

 

 

 

 

 

 

 

 

3

TC1

CAP3+

14

 

 

+

3

TC1

CAP3+ 14

 

 

 

 

 

 

 

C2

 

4 TC2

CAP2+ 13

 

 

 

4

TC2

CAP2+

13

+

– C4

+

 

 

 

 

 

 

 

–

C3

 

 

C2

–

+

 

5

POFF

CAP2– 12

 

5

POFF

CAP2– 12

 

 

+

RRV

6

VSS

CAP1+

11

C1

+

–

6

VSS

CAP1+ 11

+

– C3

 

 

(100kΩ=1MΩ)

 

 

 

 

 

 

 

 

–

 

 

 

C1

–

 

 

7

OSC1

CAP1– 10

 

 

7

OSC1

CAP1– 10

 

 

 

8

OSC2

VDD

9

 

 

 

8

OSC2

VDD 9

 

 

Figure 8.3 Parallel Connection

Series Connection

When S1F76640 is connected in series (VDD and VO in the previous stage are connected to GND and VDD in the next stage respectively), the output voltage can be increased more. But the series connection makes the output impedance high. Figure 8.4 shows an example of the series connection to get VO=25V from VDD=5V and to stabilize it.

1

RV

VRI 16

 

2

VREG

VO 15

 

3

TC1

CAP3+ 14 +

4

TC2

CAP2+ 13

–

 

5

POFF

CAP2– 12

 

6

VSS

CAP1+ 11

C1+

 

 

 

7

OSC1

CAP1– 10

–

 

8

OSC2

VDD 9

 

D1

Load

1

RV

VRI

16

+

 

–

 

 

 

 

 

2

VREG

VO 15

 

 

 

3

TC1

CAP3+ 14

 

 

 

4

TC2

CAP2+

13

+

 

 

 

 

 

+

5

POFF

CAP2–

12

–

–

 

 

 

 

 

 

 

+

6

VSS

CAP1+ 11

 

 

7

OSC1

CAP1– 10

 

–

 

 

 

 

8

OSC2

VDD

9

 

 

 

Figure 8.4 Series Connection

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EPSON

S1F70000 Series Technical Manual