Epson Power Supply IC S1F70000 Technical Manual page 87

S1F76640 Series
CAP1+=2V
V =5V
DD
GND=0V
Figure 5-3
Example of 2 times step-up
potential relations
Note 1 : At the 3 times step-up time, 2 times step-up output (–10V) cannot be taken out from the CAP2– pin.
Note 2 : At the 4 times step-up time, 2 times step-up output (–10V) cannot be taken out from the CAP2– pin.
Note 3 : At the 4 times step-up time, 3 times step-up output (–15V) cannot be taken out from the CAP3– pin.
Reference Voltage Generator, Voltage Stabilization Circuit
The reference voltage generator generates reference voltage necessary for operation of the voltage stabilization
circuit and adds temperature gradient to reference voltage. Three temperature gradients are available, and signal
from the temperature gradient selection circuit select one of them.
The voltage stabilization circuit stabilizes the step-up output voltage V
an external resistor R
RV
V output voltage can be set to optional voltages between the reference voltage V
REG
The voltage stabilization circuit has power off function and can control ON/OFF of V
signals from the system side (microprocessor, etc.) When P
P is Low (GND), it is turned off. When the control is not necessary, P
OFF
2–44
CAP2+=3V
=10V
DD
Example of 3 times step-up
is connected as shown in Figure 5-5 and the potential of the intermediate tap is changed,
V
SS
P
OFF
R
1
RV
V
REG
Figure 5-6 Voltage Stabilization Circuit
=15V
DD
Note 1
V =5V
DD
GND=0V
Figure 5-4
potential relations
Control signal
R =100k to 1M
RV
V
REG
is high (V
OFF
EPSON
CAP3+=4V =20V
DD
Note 3
Note 2
V =5V
DD
GND=0V
Figure 5-5
Example of 4 times step-up
potential relations
and outputs optional voltages. When
O
and V .
RV O
R
RV
· V
=
RV
R
1
output according to
REG
), V output is turned on, and when
DD REG
is fixed to High (V
OFF
).
DD
S1F70000 Series
Technical Manual