S-812C Seiko Instruments Inc, S-812C Datasheet - Page 9

• Manufacturer Part Number: S-812C
• Description: HIGH OPERATING VOLTAGE CMOS VOLTAGE REGULATOR
• Manufacturer: Seiko Instruments Inc

Rev.1.0
„Application Circuits
1. Output Current Boost Circuit
2. Constant Current Circuit
As shown in Figure 11, the output current
can be boosted by externally attaching a
PNP transistor.
base current of the PNP transistor so that the
output voltage V
specified in the S-812C if the sufficient base-
emitter voltage V
transistor is obtained between input voltage
V
The S-812C series can be served in a
constant current circuit as shown in the
figure 12. Constant current I
from the following equation:
I
the effective output voltage.
Please note that in case of the circuit
shown in the figure 12 (1) the magnitude of
the constant current I
driving ability of the S-812C.
The circuit shown in the figure 12 (2) can,
however, provide the current beyond the
driving ability of the S-812C by combining a
constant current circuit with a current boost
circuit. The maximum input voltage for the
constant current circuit is the sum of the
voltage V
recommended
between the S-812C power source VIN
and VSS pins or between output VOUT
and VSS pins because rush current flows
at power-on.
3. Output Voltage Adjustment Circuit
The output voltage can be increased using the configuration shown in the figure 13. The output Voltage V
can be calculated using the following equation;
Value of R1 and R2 should be determined so as not to be affected by the current consumption I
O
where V
IN
= (V
of the circuit shown in figure 11 is not enough in some applications, evaluation for output variation due to
power-on, power line variation and load variation in actual condition is needed before massproduction.
protection for the boost circuit.
As the transient response characteristics
Note that the short-circuit protection incorporated in the S-812C series does not work as a short-circuit
and S-812C power source pin VIN.
V
OUT
OUT
OUT
1 = V
O
(E)
of the device and 16 V. It is not
(E) is the effective output voltage
OUT
RL) +I
to
(E) x (R1 + R2)
OUT
BE
The S-812C controls the
attach
SS,
becomes the voltage
to turn on the PNP
O
is limited by the
where V
O
a
is calculated
HIGH OPERATING VOLTAGE CMOS VOLTAGE REGULATOR
capacitor
OUT
R1 + R2 x I
(E) is
Seiko Instruments Inc.
.
SS
,
(1) Constant Current Circuit
(2) Constant Current Boost Circuit
V
GND
V
IN
GND
IN
GND
V
IN
Figure 11 Output Current Boost Circuit
C
C
VIN
IN
C
Figure 12 Constant Current Circuits
R1
IN
R1
IN
Tr1
VSS
Tr1
ON/OFF
S-812C
Series
VIN
VIN
S-812C
VSS
Series
S-812C
Series
ON/OFF
VOUT
VSS
ON/OFF
VOUT
VOUT
S-812C Series
V
V
O
O
RL
RL
C
SS
L
I
.
o
I
O
V0
V0
V
OUT
Device
Device
OUT
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