Application Example - Epson Power Supply IC S1F70000 Technical Manual

APPLICATION EXAMPLE

2 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 C
V (Pin No. 15), and 3 times step-up voltage is obtained from V
O
C is also removed and CAP2+ (Pin No. 13) is short-circuited to V
2
is obtained from V (CAP2+).
O
V
I
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 V
cuit. In this application example, both outputs from V
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.
V
REG
C
5
R +R
1 2
V = ·V
REG RV
R
1
(R =R +R )
RV 1 2
Figure 8-2 Operation of 4 Times Step-up + Stabilization Circuit (Temperature Gradient CT1 is
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 R
noise influence. (In this case, however, more current comes to be consumed at R
S1F70000 Series
Technical Manual
1 RV
2 V
REG
3 TC1
4 TC2
5 P
OFF
6 V
SS
7 OSC1
8 OSC2
Figure 8-1 4 times step-up circuit
REG
1
2
Note 1
3
R
2
+
4
–
R 5
1
6
Note 2
7
V
I
8
selected.)
EPSON
is removed and CAP3+ (Pin No. 14) is short-circuited to
3
(CAP3+). In case of 2 times step-up, the capacitor
O
(Pin No. 15), and 2 times step-up voltage (10V)
O
V 16
RI
V 15
O
CAP3+ 14
+
CAP2+ 13
C
–
2
CAP2– 12
CAP1+ 11 +
C
1
–
CAP1– 10
V 9
DD
output by means of the temperature gradient selection cir-
and V can be indicated at the same time. Also,
O REG
RV V 16
RI
V V 15
REG O
TC1 CAP3+ 14
TC2 CAP2+ 13
P CAP2– 12
OFF
V CAP1+ 11
SS
OSC1 CAP1– 10
OSC2 V 9
DD
S1F76640 Series
4V
I
+
C
3
–
+
C
–
4
+
+
C
–
3
– C +
2
C
–
4
+
C
–
1
value small for reducing
RV
.)
RV
2–57