HA17723/F/P
HA17723 Applications
Fixed Voltage Source in Series
Low Voltage (2 to 7 V) Regulator: Figure 1 shows the construction of a basic low voltage regulator. The
divider (resistors R1 and R2) from VREF makes the reference voltage, which will be provided to the
noninverted input of the error amplifier, less than output voltage. In the fixed voltage source where the
output voltage will be fed back to the error amplifier directly as shown in figure 1. Output voltage will be
divided VREF since the output voltage is equal to the reference voltage.
Thus, the output voltage VOUT is:
VOUT = nVREF,
n=
R2
R1 + R2
CREF
1µF
VIN
VCC
VC
VREF VOUT
R1
2.15kΩ
CL
RSC = 0
R2
4.99kΩ
CS
VIN(+) VIN(–)
R3 1.5kΩ
C1
VEE COMP 100pF
VOUT
Figure 1 Low Voltage (2 to 7 V) Regulator
High Voltage (7 to 37 V) Regulator: Figure 2 shows the construction of a regulator whose output voltage
is higher than the reference voltage, VREF. VREF is added to the non-inverted input of the error amplifier via
a resistor, R3. The feedback voltage is produced by dividing the output voltage with resistors R1 and R2.
Thus, the output voltage VOUT is:
VOUT =
VREF
n
,
n = R2
R1 + R2
R3
3.8kΩ
VIN
VCC
VREF
VIN(+)
VEE
VC
VOUT
CL
CS
VIN(–)
COMP
RSC = 0 VOUT
C1
100pF
R1
7.87kΩ
R2
7.15kΩ
Figure 2 High Voltage (7 to 37 V) Regulator
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