S1F78100Y2A Epson Electronics America, Inc., S1F78100Y2A Datasheet - Page 143

• Manufacturer Part Number: S1F78100Y2A
• Description: High Precision Voltage Regulators
• Manufacturer: Epson Electronics America, Inc.

S1F79100Y Series
Differential amplifier
The built-in differential amplifier generates a potential
at point X that adjusts the gate bias of the output transis-
tor if there is any difference betweeen V
TYPICAL APPLICATIONS
Current Booster
At the cost of a small increase in current consumption,
the voltage is regulated while maintaining high current
output.
External Voltage Converter
The following circuit raises the output voltage of a
S1F79100Y series IC.
3–36
V
V
SS
I
V
V
SS
V
REF
I
V
V
SS
I
X
S1F79100Y
GND
P1
N1
V
I
V
S1F79100Y
I
N2
P2
I
OPR
GND
V
O
V
r
To output
transistor
V
V
REG
O
REF
R
R
I
B
1
2
and V
V
O
V
REG
O
EPSON
.
Output transistor
The output side of the p-channel MOS transistors in the
output transistor circuit is connected to the voltage di-
vider resistors in the feedback loop.
The following equation shows the relationship between
the old and new voltages.
V
Note that the application must supply a bias current, I
high enough to offset the increase in voltage across R
due to I
An alternative circuit for raising the output voltage is
shown in the following figure.
This configuration, however, introduces two design
problems.
1. It reduces the output voltage by V
2. It is sensitive to fluctuations in V
O
V
age drop across the diode.
in diodes, operating temperatures and I
V
SS
V
SS
= — — — — — V
I
R
OPR
1
R
+ R
2
.
C
2
V
I
REF
V
I
R
S1F79100Y
GND
I
+
–
SS
V
O
F
F
, the forward volt-
due to differences
C
O
Technical Manual
S1F70000 Series
SS
V
1
.
R
V
R
REG
1
2
R1
V
V
O
O
B
1
,