Epson Power Supply IC S1F70000 Technical Manual page 76

Setup conditions of Figure 2.11
First stage
• Internal clock : ON (Low Output mode)
• Booster circuit : ON
• Regulator : OFF
Power-off procedure
• In Figure 2.11, when the P
the first and second stages. However, the regulator at the second stage does not stop. Therefore, the voltage that
is approximately V appears at V
I
• To set the V pin to high-impedance state, set both P
REG
Application in other setup conditions
1 When used in the High Output mode
• Connect the FC pin of the first-stage S1F76540 to the V
2 When changing the temperature coefficient (C
• Change the TC1 and TC2 pin setup by following the definition of Table 2.7.
Larger Time Boosting Using Diodes
The S1F76540 can be configured to have the five-time
or larger voltage boosting and regulation by adding ex-
ternal diodes. As the booster output impedance in-
creases due to the diode forward voltage drop (V
diodes having a smaller V
F
V
REG
V
DD
V
I
Figure 2.12 Wiring example for 6-time boosting using diodes
S1F70000 Series
Technical Manual
pin of the first-stage S1F76540 is set to low (V
OFF2
pin during |V
REG REG
)
T
), the
F
are recommended to use.
1
C
REG
+
2
R1 R2
3
4
5
6
+ 7
8
C
I
EPSON
Second stage
• Internal clock : OFF
• Booster circuit : ON
• Regulator : ON (if C
I
| > |V | setup.
I
and P pins to low at the first and second stages.
OFF1 OFF2
pin.
I
Figure 2.12 gives a wiring example of 6-time booster
and regulator that use two diodes. The wiring between
V and V must be minimal. Figure 2.13 provides the
O RI
potential relationship.
+
V C2P 16
O
+
V C2N 15
RI
C2
V C3N 14
REG
C1
RV C1N 13
V C1P 12
DD
+
FC V 11
I
TC1 P 10
OFF1
TC2 P 9
OFF2
S1F76540 Series
= –0.04%/ C)
T
), voltage boosting is stopped at
V
O
D1 D2
C4
C5 C
O
+ +
C3
+
2–33
'