Functional Descriptions - Epson Power Supply IC S1F70000 Technical Manual

FUNCTIONAL DESCRIPTIONS

S1F78100Y Series is a fixed positive output type volt-
age regulator of series regulator system and is fitted
with an output control MOS transistor between the in-
put and output pins as shown in the figure below. The
voltage regulator feeds back voltages (V
with the built-in resistors R
V
DD
(2pin)
V
SS
(1pin)
S1F70000 Series
Technical Manual
) divided
REG
and R connected between
1 2
R
V =
O
(Output control transistor)
(Operational amplifier)
EPSON
the output pin (V pin) and the V
O
them with the reference voltage (V
stable output voltage (V
age by controlling the gate voltage of the output control
transistor. The output voltage is fixed inside and is de-
cided with the following formula:
+R
1 2
·V
REF
R
1
R2
(V )
REG
+
–
R1
V
REF
S1F78100Y Series
pin to compare
SS
) and outputs the
REF
) not depending on input volt-
0
V
O
(3pin)
3–3