S1F76610 Series

Serial Connection

Connecting two or more chips in series obtains a higher output voltage than can be obtained using a parallel

<Precautions when connecting loads>

In case of series connections, when connecting loads between the first stage VDD (or other potential of the second stage VDD or up) and the second stage VREG as shown in Fig. 2-13, be cautions about the following point.

*When normal output is not occurring at the VREG ter- minal such as at times of starting up or when turning the VREG off by POFF signals, if current flows into the second stage VREG terminal through the load from

connection, however, this also raises the output imped- ance.

the first stage VDD (or other potential of the second stage VDD or up) to cause a voltage exceeding the absolute maximum rating for the second stage VDD at the VREG terminal, normal operation of the IC may be hampered. Consequently, When making a series connection, insert a diode D1 between the second stage VI and VREG as shown in Fig. 2-13 so that a voltage exceeding the second stage VDD or up may not be applied to the VREG terminal.

S1F76610

Series

 

 

VDD = 0V

 

 

 

 

 

 

 

 

VDD'= VI = –5V

 

 

 

 

 

 

 

 

 

 

 

 

10∝F

1

14

 

 

+

1

14

100kΩ

Load

 

+

 

 

 

 

 

 

 

10∝F

 

 

 

to

 

 

–

2

13

1MΩ

–

2

13

1MΩ

+

5V

 

 

 

 

 

 

 

 

10∝F

 

3

12

 

 

+

3

12

 

–

 

 

 

10∝F

 

 

 

 

4

11

 

–

4

11

 

 

 

 

5

10

 

 

 

5

10

 

 

 

 

6

9

VO = –10V= VI

 

 

6

9

 

VREG'= –15V

 

 

7

8

 

 

 

7

8

VO = –20V

 

10∝F

 

 

 

 

VI = –5V

 

 

 

+

–

 

 

 

 

 

 

 

 

 

 

 

 

 

+ –

 

 

 

10∝F

 

 

 

 

 

 

 

 

 

 

 

 

 

Positive Voltage Conversion

Adding diodes converts a negative voltage to a positive one.

To convert the voltage tripler shown earlier to a voltage doubler, remove C2 and D2, and short circuit D3. Small Schottky diodes are recommended for all these diodes. The resulting voltage is lowered by VF, the voltage drop in the forward direction for each diode used. For ex- ample, if VDD = 0V, VI = –5V, and VF = 0.6V, the resulting voltages would be as follows.

• For a voltage tripler,

VO = 10 – (3× 0.6) = 8.2V

•For a voltage doubler,

VO = 5 – (2× 0.6) = 3.8V

D1

VDD = 0 V

 

 

 

 

 

D1

 

 

 

 

C1

 

 

 

 

 

 

 

 

 

 

 

 

 

10

∝F

1

14

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D2

 

 

 

 

C2

2

13

 

ROSC

 

 

 

 

 

 

 

 

 

10

∝F

 

 

 

 

 

 

 

 

5 V

 

 

 

 

 

3

12

 

1 MΩ

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

 

 

 

D3

 

 

 

 

 

 

4

11

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

9

 

 

 

 

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

8

 

 

 

 

 

 

 

 

VO = 8.2 V

 

 

 

 

 

 

 

 

 

 

 

 

 

C3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10 ∝F

 

 

 

 

 

 

VI =

–5 V

 

 

 

 

 

 

 

 

 

S1F70000 Series Technical Manual

EPSON

2–13