S1F76640 Series

APPLICATION EXAMPLE2 Times Step-up, 3 Times Step-up and 4 Times Step-up

Figure 8.1 shows the connection for getting 4 times step-up output of an input voltage by operating the step-up circuit only. In case of 3 times step-up, the capacitor C3 is removed and CAP3+ (Pin No. 14) is short-circuited to VO (Pin No. 15), and 3 times step-up voltage is obtained from VO(CAP3+). In case of 2 times step-up, the capacitor C2 is also removed and CAP2+ (Pin No. 13) is short-circuited to VO (Pin No. 15), and 2 times step-up voltage (10V) is obtained from VO (CAP2+).

 

1

RV

VRI

16

 

 

 

2

VREG

VO

15

 

4VI

 

3

TC1

CAP3+ 14

 

 

 

4

TC2

CAP2+ 13

+

+

 

5

POFF

CAP2– 12

– C2

– C3 +

 

 

– C4

 

 

 

 

 

 

 

6

VSS

CAP1+ 11

+

 

 

7

OSC1

CAP1– 10

– C1

 

 

 

 

VI

8 OSC2

VDD

9

 

 

Figure 8-1 4 times step-up circuit

4 Times Step-up + Stabilization Circuit

Figure 8-2 shows an application example for stabilizing step-up outputs obtained in 8-(1) through the stabilization circuit and for providing temperature gradient to VREG output by means of the temperature gradient selection cir- cuit. In this application example, both outputs from VO and VREG can be indicated at the same time. Also, operation of 3 times step-up + stabilization circuit is possible by using the 3 times step-up operation mentioned in 8- (1), and operation of 2 times step-up + stabilization circuit is possible by using the 2 times step-up operation.

 

 

1

RV

VRI 16

 

 

VREG

Note 1

2

VREG

VO 15

 

 

 

3

TC1

CAP3+ 14

 

 

 

R2

 

 

 

 

 

 

 

 

C5

+

4

TC2

CAP2+ 13

+

+

 

–

5

POFF

CAP2– 12

– C2

– C3 +

 

R1

 

– C4

 

 

 

 

 

 

 

 

6

VSS

CAP1+ 11

+

 

Note 2

7

OSC1

CAP1– 10

– C1

 

 

 

VREG= R1+R2 ·VRV

VI

8

OSC2

VDD 9

 

 

R1

 

 

 

(RRV=R1+R2)

 

 

 

 

 

 

Figure 8-2 Operation of 4 Times Step-up + Stabilization Circuit (Temperature Gradient CT1 is

selected.)

Note 1 : Since input impedance at the RV pin (No. 1) is high, it is necessary to use a shielded wire as a measure against noise in case of a long connection. It is also effective to make the RRV value small for reducing noise influence. (In this case, however, more current comes to be consumed at RRV.)

S1F70000 Series

EPSON

2–57

Technical Manual

 

 

S1F76640

Series