VOLTAGE REGULATOR
FOR MIDDLE OUTPUT CURRENT
R×5RE SERIES
APPLICATION MANUAL
NO.EA-016-0006
VOLTAGE REGULATOR
FOR MIDDLE OUTPUT CURRENT
1
R
×
5RE SERIES
OUTLINE
The R×5RE Series are voltage regulator ICs with high output voltage accuracy and ultra-low quiescent
current by CMOS process. Each of these ICs consists of a voltage reference unit, an error amplifier, a driver
transistor, and resistors for setting output voltage, and a current limit circuit. By use of these ICs, a con-
stant voltage power supply circuit with high efficiency can be constructed because the dropout voltage and
quiescent current of these ICs are very small. Furthermore, theses ICs have a built-in current limit circuit.
The output voltage of these ICs is fixed with high accuracy.
Two types of packages, TO-92 and SOT-89 (Mini-power Mold) are available.
• Ultra-low Quiescent Current ...........................TYP. 1.1µA (R×5RE30A,VIN=5.0V)
• Ultra-low Dropout Voltage ...............................TYP. 0.5V (R×5RE50A,IOUT=60mA)
• Large Output Current ......................................TYP. 120mA (R×5RE50A)
• Low Temperature-Drift Coefficient of Output Voltage ...........................TYP. ±100ppm/˚C
• Broad Operating Voltage Range ......................MAX. 10.0V
• Excellent Line Regulation ................................TYP. 0.1%/V
• High Accuracy Output Voltage ........................±2.5%
• Output Voltage...................................................Stepwise setting with a step of 0.1V in the range of 2.0V to 6.0V is
possible (refer to Selection Guide)
• Two Types of Packages ..................................TO-92, SOT-89 (Mini-power Mold)
FEATURES
APPLICATIONS
• Power source for battery-powered equipment.
• Power source for cameras, video instruments such as camcorders, VCRs, and hand- held communication equipment.
• Precision voltage references.
BLOCK DIAGRAM
2
1
3
Vref
VOUT
GND
VIN
–
+
2
R×5RE××××–×× ← Part Number
↑↑↑↑↑
abcde
SELECTION GUIDE
The package type, the output voltage, the packing type, and the taping type of R×5RE Series can be
designated at the user's request by specifying the part number as follows.
}
}
For example, the product with Package Type SOT-89,Output Voltage 5.0V,Version A and Taping Type T1 are
designated by Part Number RH5RE50AA-T1.
Code Contents
Designation of Package Type:
a E: TO-92
H: SOT-89 (Mini-power Mold)
bSetting Output Voltage (VOUT):
Stepwise setting with a step of 0.1V in the range of 2.0V to 6.0V is possible.
cA
Designation of Packing Type:
d A: Taping
C: Antistatic bag for TO-92 and samples
Designation of Taping Type:
Ex. TO-92 : RF, RR, TZ
eSOT-89: T1, T2
(refer to Taping Specifications)
“TZ” and “T1” are prescribed as a standard.
R×5RE
3
• TO-92
PIN CONFIGURATION
• SOT-89
PIN DESCRIPTION
• TO-92 • SOT-89
Pin No. Symbol
1 GND
2VIN
3VOUT
Pin No. Symbol
1 GND
2VIN
3VOUT
123
(mark side)
123
(mark side)
R×5RE
4
ABSOLUTE MAXIMUM RATINGS
Symbol Item
VIN Input Voltage
VOUT Output Voltage
IOUT Output Current
PDPower Dissipation
Topt Operating Temperature
Tstg Storage Temperature
Tsolder Lead Temperature (Soldering)
Rating Unit
+12 V
–0.3 to VIN+0.3 V
300 mA
300 mW
–40 to +85 ˚C
–55 to +25 ˚C
260˚C, 10s
R×5RE
Absolute Maximum ratings are threshold limit values that must not be exceeded even for an instant under any
conditions. Moreover, such values for any two items must not be reached simultaneously. Operation above
these absolute maximum ratings may cause degradation or permanent damage to the device. These are stress
ratings only and do not necessarily imply functional operation below these limits.
ABSOLUTE MAXIMUM RATINGS
5
ELECTRICAL CHARACTERISTICS
Symbol Item
VOUT Output Voltage
IOUT Output Current
∆VOUT Load Regulation
∆IOUT
VDIF Dropout Voltage
ISS Quiescent Current
∆VOUT
∆VIN Line Regulation
VIN Input Voltage
Ilim Current Limit
∆VOUT Output Voltage
∆Topt Temperature Coefficient
Conditions MIN. TYP. MAX. Unit
VIN=4.0V,IOUT=10mA 1.950 2.000 2.050 V
VIN=4.0V 40 60 mA
VIN=4.0V
1mA≤IOUT≤50mA 40 80 mV
IOUT=30mA 0.5 0.7 V
VIN=4.0V 1.0 3.0 µA
IOUT=10mA
VOUT+1.0V≤VIN≤10V 0.1 %/V
10 V
240 mA
IOUT=10mA ±100 ppm/˚C
–40˚C≤Topt≤85˚C
Topt=25˚C
• R×5RE30A Topt=25˚C
R×5RE
Symbol Item
VOUT Output Voltage
IOUT Output Current
∆VOUT Load Regulation
∆IOUT
VDIF Dropout Voltage
ISS Quiescent Current
∆VOUT
∆VIN Line Regulation
VIN Input Voltage
Ilim Current Limit
∆VOUT Output Voltage
∆Topt Temperature Coefficient
Conditions MIN. TYP. MAX. Unit
VIN=5.0V,IOUT=10mA 2.925 3.000 3.075 V
VIN=5.0V 50 80 mA
VIN=5.0V
1mA≤IOUT≤60mA 40 80 mV
IOUT=40mA 0.5 0.7 V
VIN=5.0V 1.1 3.3 µA
IOUT=10mA
VOUT+1.0V≤VIN≤10V 0.1 %/V
10 V
240 mA
IOUT=10mA ±100 ppm/˚C
–40˚C≤Topt≤85˚C
6
• R×5RE50A Topt=25˚C
R×5RE
• R×5RE40A Topt=25˚C
Symbol Item
VOUT Output Voltage
IOUT Output Current
∆VOUT Load Regulation
∆IOUT
VDIF Dropout Voltage
ISS Quiescent Current
∆VOUT
∆VIN Line Regulation
VIN Input Voltage
Ilim Current Limit
∆VOUT Output Voltage
∆Topt Temperature Coefficient
Conditions MIN. TYP. MAX. Unit
VIN=6.0V,IOUT=10mA 3.900 4.000 4.100 V
VIN=6.0V 65 100 mA
VIN=6.0V
1mA≤IOUT≤70mA 40 80 mV
IOUT=50mA 0.5 0.7 V
VIN=6.0V 1.2 3.6 µA
IOUT=10mA
VOUT+1.0V≤VIN≤10V 0.1 %/V
10 V
240 mA
IOUT=10mA ±100 ppm/˚C
–40˚C≤Topt≤85˚C
Symbol Item
VOUT Output Voltage
IOUT Output Current
∆VOUT Load Regulation
∆IOUT
VDIF Dropout Voltage
ISS Quiescent Current
∆VOUT
∆VIN Line Regulation
VIN Input Voltage
Ilim Current Limit
∆VOUT Output Voltage
∆Topt Temperature Coefficient
Conditions MIN. TYP. MAX. Unit
VIN=7.0V,IOUT=10mA 4.875 5.000 5.125 V
VIN=7.0V 80 120 mA
VIN=7.0V
1mA≤IOUT≤80mA 40 80 mV
IOUT=60mA 0.5 0.7 V
VIN=7.0V 1.3 3.9 µA
IOUT=10mA
VOUT+1.0V≤VIN≤10V 0.1 %/V
10 V
240 mA
IOUT=10mA ±100 ppm/˚C
–40˚C≤Topt≤85˚C
7
• R×5RE60A Topt=25˚C
R×5RE
Symbol Item
VOUT Output Voltage
IOUT Output Current
∆VOUT Load Regulation
∆IOUT
VDIF Dropout Voltage
ISS Quiescent Current
∆VOUT
∆VIN Line Regulation
VIN Input Voltage
Ilim Current Limit
∆VOUT Output Voltage
∆Topt Temperature Coefficient
Conditions MIN. TYP. MAX. Unit
VIN=8.0V,IOUT=10mA 5.850 6.000 6.150 V
VIN=8.0V 80 120 mA
VIN=8.0V
1mA≤IOUT≤80mA 40 80 mV
IOUT=60mA 0.5 0.7 V
VIN=8.0V 1.4 4.2 µA
IOUT=10mA
VOUT+1.0V≤VIN≤10V 0.1 %/V
10 V
240 mA
IOUT=10mA ±100 ppm/˚C
–40˚C≤Topt≤85˚C
8
ELECTRICAL CHARACTERISTICS BY OUTPUT VOLTAGE
R×5RE
VIN–
VOUT
=2.0V
1mA≤
40 60
IOUT
≤50mA
VIN–
VOUT
=2.0V
1mA≤
IOUT
≤60mA
50 80
VIN–
VOUT
=2.0V 40 80
1mA≤
IOUT
≤70mA
65 100
VIN–
VOUT
=2.0V
1mA≤
80 120 IOUT
≤80mA
R×5RE20A 1.950 2.000 2.050
R×5RE21A 2.048 2.100 2.152
R×5RE22A 2.145 2.200 2.255
R×5RE23A 2.243 2.300 2.357
R×5RE24A 2.340 2.400 2.460
R×5RE25A 2.438 2.500 2.562
R×5RE26A 2.535 2.600 2.665
R×5RE27A 2.633 2.700 2.767
R×5RE28A 2.730 2.800 2.870
R×5RE29A 2.828 2.900 2.972
R×5RE30A 2.925 3.000 3.075
R×5RE31A 3.023 3.100 3.177
R×5RE32A 3.120 3.200 3.280
R×5RE33A 3.218 3.300 3.382
R×5RE34A 3.315 3.400 3.485
R×5RE35A 3.413 3.500 3.587
R×5RE36A 3.510 3.600 3.690
R×5RE37A 3.608 3.700 3.792
R×5RE38A 3.705 3.800 3.895
R×5RE39A 3.803 3.900 3.997
R×5RE40A 3.900 4.000 4.100
R×5RE41A 3.998 4.100 4.202
R×5RE42A 4.095 4.200 4.305
R×5RE43A 4.193 4.300 4.407
R×5RE44A 4.290 4.400 4.510
R×5RE45A 4.388 4.500 4.612
R×5RE46A 4.485 4.600 4.715
R×5RE47A 4.583 4.700 4.817
R×5RE48A 4.680 4.800 4.920
R×5RE49A 4.778 4.900 5.022
R×5RE50A 4.875 5.000 5.125
R×5RE51A 4.973 5.100 5.227
R×5RE52A 5.070 5.200 5.330
R×5RE53A 5.168 5.300 5.432
R×5RE54A 5.265 5.400 5.535
R×5RE55A 5.363 5.500 5.637
R×5RE56A 5.460 5.600 5.740
R×5RE57A 5.558 5.700 5.842
R×5RE58A 5.655 5.800 5.945
R×5RE59A 5.753 5.900 6.047
R×5RE60A 5.850 6.000 6.150
Output Voltage OutputCurrent Load Regulation
Part Number VOUT(V) IOUT(mA) ∆VOUT/∆IOUT(mV)
Conditions
MIN. TYP. MAX.
Conditions
MIN. TYP.
Conditions
TYP. MAX.
VIN–
VOUT
=2.0V
IOUT
=10mA
VIN–
VOUT
=2.0V
IOUT
=30mA
IOUT
=40mA
0.5 0.7
IOUT
=
50mA
IOUT
=60mA
Dropout Voltage
VDIF(V)
Conditions
TYP. MAX.
9
R×5RE
Topt=25˚C
1.0 3.0
1.1 3.3
IOUT
=10mA
IOUT
VIN–
=10mA
VOUT 1.2 3.6 0.1 10 240 ±100
=2.0V VOUT+
–40˚C
≤
1.0V≤Topt
VIN ≤85˚C
≤10V
1.3 3.9
1.4 4.2
Quiescent Current Line Regulation
Input Voltage Current Limit
Output Voltage Tempco.
Iss(µA) ∆VOUT/∆VIN(%/V) VIN(V) Ilim(mA)
∆VOUT/∆T(ppm/˚C)
Conditions
TYP. MAX.
Conditions
TYP. MAX. TYP.
Conditions
TYP.
10
OPERATION
Output Voltage VOUT divided at the node between
Registers R1 and R2 is compared with Reference Voltage
by Error Amplifier, so that a constant voltage is output.
TEST CIRCUITS
FIG. 2 Test Circuit FIG. 3 Quiescent Current Test Circuit
FIG. 4 Line Transient Response Test Circuit
FIG. 1 Brock Diagram
R×5RE
GNDGND
VIN
–
+
Error Amplifire
VOUT
R2
R1
Vref
CI
1µF Co
1µF
VIN
GND
R×5RE
SERIES VOUT IOUT VOUT
VIN
++
ISS
CI
1µF
VIN
GND
R×5RE
SERIES VOUT
VIN
+
Ro
Co
0.1µF
P.G GND
R×5RE
SERIES
VOUT VOUT
VIN
+
11
TYPICAL CHARACTERISTICS
1) Output Voltage vs. Output Current
R×5RE40A
R×5RE50A
R×5RE50A
R×5RE
Output Current IOUT(mA)
Output Voltage VOUT(V)
0
3.7
3.8
3.9
4.1
4.0
VIN=6.0V
50 100 150 200
Topt=–40˚C
85˚C
25˚C
4.7
4.8
4.9
5.1
5.0
VIN=7.0V
050 100 150 200 250
Output Voltage VOUT(V)
Output Current IOUT(mA)
with heatsink
without heatsink
4.7
4.8
4.9
5.1
5.0
VIN=7.0V
050 100 150 200 250
heatsink
30×30×1mm
Output Voltage VOUT(V)
Output Current IOUT(mA)
4.7
4.8
4.9
5.1
5.0
VIN=7.0V
0 50 100 150 200 250 300 350
25˚C
Topt=–40˚C
85˚C
R×5RE30A
Output Voltage VOUT(V)
Output Current IOUT(mA)
2.7
2.8
2.9
3.1
3.0
VIN=5.0V
050 100 150 200 250
Topt=–40˚C
25˚C
85˚C
R×5RE20A
2) Output Voltage vs. Input Voltage
Topt=25˚C
245367
Input Voltage VIN(V)
Output Voltage VOUT(V)
1.98
1.96
2.00
2.02
2.04
IOUT=1µA
1mA 10mA
12
R×5RE30A
R×5RE40A
R×5RE30A
R×5RE40A
R×5RE
R×5RE50A R×5RE50A
Topt=25˚C
2.0 3.0 3.52.5 4.0 4.5
Input Voltage VIN(V)
Output Voltage VOUT(V)
2.0
2.2
1.8
2.4
2.6
2.8
3.0
3.2
3.4
IOUT=1mA
50mA
10mA
2.5 4.53.5 5.5
Input Voltage VIN(V)
Topt=25˚C
Output Voltage VOUT(V)
3.4
3.2
3.6
3.8
4.0
4.2
IOUT=1mA
50mA
10mA
Topt=25˚C
3.0 5.0 6.04.0 7.0 8.0
Input Voltage VIN(V)
Output Voltage VOUT(V)
2.96
2.95
2.97
2.98
2.99
3.00
IOUT=1µA
1mA 10mA
Topt=25˚C
467589
Input Voltage VIN(V)
Output Voltage VOUT(V)
3.98
3.96
4.00
4.02
4.04
4.06
1mA
IOUT=1µA
10mA
Topt=25˚C
4.54.0 5.5 6.05.0 6.5
Input Voltage VIN(V)
Output Voltage VOUT(V)
4.4
4.2
4.6
4.8
5.0
5.1
IOUT=1mA
50mA
10mA
Topt=25˚C
6589710
Input Voltage VIN(V)
Output Voltage VOUT(V)
4.97
4.98
4.95
4.96
4.99
5.00
5.01
5.02
5.03
5.04
5.05
10mA
IOUT=1µA
1mA
13
R×5RE30A R×5RE40A
R×5RE50A
3) Dropout Voltage vs. Output Curret
R×5RE
Output Current IOUT(mA)
Dropout Voltage VDIF(V)
020 40 60 80 100
Topt=–40˚C
25˚C
85˚C
0.0
0.4
0.6
0.2
0.8
1.0
1.2
1.4
Output Current IOUT(mA)
Dropout Voltage VDIF(V)
020 40 60 80 100
85˚C
25˚C
Topt= –40˚C
0.0
0.4
0.5
0.7
0.6
0.2
0.3
0.1
0.8
Output Current IOUT(mA)
Dropout Voltage VDIF(V)
020 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
25˚C
Topt=–40˚C
85˚C
R×5RE30A
4) Output Voltage vs.Temperature
Temperature Topt(˚C)
Output Voltage VOUT(V)
-50-30-101030507090
2.9
3.0
3.1 IOUT=10mA
R×5RE40A
Temperature Topt(˚C)
Output Voltage VOUT(V)
3.9
4.0
4.1
-50-30-101030507090
IOUT=10mA
14
R×5RE50A
R×5RE20A
5) Quiescent Current vs. Input Voltage
R×5RE
R×5RE40A R×5RE50A
Temperature Topt(˚C)
Output Voltage VOUT(V)
4.9
4.8
5.0
5.2
5.1
-50-30-101030507090
IOUT=10mA
Input Voltage VIN(V)
0.6345678910
0.7
0.8
0.9
1.0
1.1
Quiescent Current Iss(µA)
Topt=25˚C
R×5RE30A
Input Voltage VIN(V)
1.0243 5678910
1.1
1.2
1.3
1.4
Quiescent Current Iss(µA)
Topt=25˚C
Input Voltage VIN(V)
1.0465 7 8 9 10 11
1.1
1.2
1.3
1.4
1.5
Quiescent Current Iss(µA)
Topt=25˚C
Input Voltage VIN(V)
0.5
0.6
76589101112
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.5
1.4
Quiescent Current Iss(µA)
Topt=25˚C
15
R×5RE20A
R×5RE50A
R×5RE40A
6) Quiescent Current vs. Temperature
R×5RE
0.5
0.7
0.9
1.1
1.3
1.7
1.5
Quiescent Current Iss(µA)
VIN=4.0V
–40 –20 0 20 40 60 80 100
Temperature Topt(˚C)
0.5
0.7
0.9
1.1
1.3
1.7
1.5
Quiescent Current Iss(µA)
VIN=6.0V
–40 –20 0 20 40 60 80 100
Temperature Topt(˚C)
R×5RE30A
0.8
1.0
1.2
1.6
1.4
Quiescent Current Iss(µA)
VIN=5.0V
–40 –20 0 20 40 60 80 100
Temperature Topt(˚C)
VIN=7.0V
0.5
0.7
0.6
0.8
0.9
1.0
1.2
1.1
1.5
1.3
1.4
Quiescent Current Iss(µA)
–20–40 0 20 40 60 80 100
Temperature Topt(˚C)
7) Dropout Voltage vs. Set Output Voltage
R×5RE SERIES
012 34 56
0.0
0.2
0.1
0.3
0.4
0.5
0.6
0.7
Set Output Voltage Vreg(V)
Dropout Voltage VDIF(V)
1mA
Topt=25˚C
10mA
IOUT=50mA
16
8) Line Transient Response (1)
R×5RE
R×5RE30A
R×5RE40A
R×5RE20A
R×5RE50A
9) Line Transient Response (2)
R×5RE20A R×5RE30A
1.5 2.0 2.5 3.0 3.5 4.0 4.5
1.0
2.0
1.5
2.5
3.0
4.5
4.5
3.5
5.0
Input Voltage/Output Voltage V(V)
IOUT=1mA
Time t(ms)
Input Voltage
Output Voltage
1.5 2.0 2.5 3.0 3.5 4.0 4.5
2.0
4.0
3.0
5.0
7.0
6.0
8.0
Input Voltage/Output Voltage V(V)
IOUT=1mA
Time t(ms)
Input Voltage
Output Voltage
1.5 2.0 2.5 3.0 3.5 4.0 4.5
1.0
3.0
2.0
4.0
6.0
5.0
7.0
Input Voltage/Output Voltage V(V)
IOUT=1mA
Time t(ms)
Input Voltage
Output Voltage
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Output Voltage
3.0
5.0
4.0
6.0
8.0
7.0
9.0
Input Voltage/Output Voltage V(V)
IOUT=1mA
Time t(ms)
Input Voltage
1.5 2.0 2.5 3.0 3.5 4.0 4.5
0.0
1.0
1.5
0.5
2.0
2.5
4.0
4.5
3.5
3.0
5.0
Input Voltage/Output Voltage V(V)
IOUT=30mA
Time t(ms)
Input Voltage
Output Voltage
1.5 2.0 2.5 3.0 3.5 4.0 4.5
1.0
3.0
2.0
4.0
6.0
5.0
7.0
Input Voltage/Output Voltage V(V)
IOUT=30mA
Time t(ms)
Input Voltage
Output Voltage
17
R×5RE40A R×5RE50A
R×5RE
1.5 2.0 2.5 3.0 3.5 4.0 4.5
2.0
4.0
3.0
5.0
7.0
6.0
8.0
Input Voltage/Output Voltage V(V)
IOUT=30mA
Time t(ms)
Input Voltage
Output Voltage
IOUT=30mA
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Output Voltage
3.0
5.0
4.0
6.0
8.0
7.0
9.0
Input Voltage/Output Voltage V(V)
Time t(ms)
Input Voltage
18
TYPICAL APPLICATION
In R×5RE Series, a constant voltage can be obtained
without using Capacitors C1 and C2. However, when the
wire connected to VIN is long, use Capacitor C1. Output
noise can be reduced by using Capacitor C2.
Insert Capacitors C1 and C2 with the capacitance of
0.1µF to 2.0µF between Input/Output Pins and GND Pin
with minimum wiring.
The output voltage can be obtained by the follow-
ing formula :
VOUT=Vreg · (1+R2/R1) + ISS · R2
Since the quiescent current of R×5RE Series is so
small that the resistances of R1 and R2 can be set as
large as several hundreds kΩand therefore the sup-
ply current of “Voltage Boost Circuit” itself can be
reduced.
Furthermore, since R×5RE Series are operated by
a constant voltage, the supply current of “Voltage
Boost Circuit” is not substantially affected by the
input voltage.
As shown in the circuit diagram, a dual power sup-
ply circuit can be constructed by using two R×5RE
Series.
This circuit diagram shows a dual power supply
circuit with an output of 3V and an output of 5V.
When the minimum output current of IC2 is larger
than ISS of IC1, Resistor R is unnecessary. Diode D is
a protection diode for the case where VOUT2
becomes larger than VOUT1.
• VOLTAGE BOOST CIRCUIT
• DUAL POWER SUPPLY CIRCUIT
R×5RE
C2
C1
VIN
GND
GND GND
R×5RE
SERIES
VOUT VOUT
VIN
++
C2
C1
VIN
GND
GND
R×5RE
SERIES
VOUT VOUT
VIN
R1
R2
ISS
+
+
C1
C2
VIN
GND
GNDGND
R×5RE20A
R×5RE30A
VOUT VOUT1
5V
VOUT2
3V
VIN
C3
GND
VOUT
VIN
R
ISS
IC1
IC2
D
++
+
*1) Vreg : Set Output Voltage of R×5RE Series.
*1
APPLICATION CIRCUITS
19
• CURRENT BOOST CIRCUIT
Output current of 120mA or more can be obtained
by the current boost circuit constructed as shown in
this circuit diagram.
• CURRENT BOOST CIRCUIT WITH OVERCURRENT LIMIT CIRCUIT
• CURRENT SOURCE
A current source with the structure as shown in
this circuit diagram can be used. Output Current
IOUT is obtained as follows :
IOUT=Vreg /R + ISS
Take care that Output Current IOUT does not exceed
its allowable current.
R×5RE
C2
GND
GND
GND
R×5RE
SERIES
VOUT VOUT
C1
VIN VIN
Tr.1
++
C2
GND
GND
GND
R×5RE
SERIES
VOUT
VOUT
VIN VIN
Tr.1
Tr.2
R1
R2
IOUT
Vbe2
++
GND
R×5RE
SERIES
C1
VIN VIN
R
IOUT
ISS
VOUT
+
A circuit for protecting Tr.1 from the destruction
caused by output short-circuit or overcurrent is shown in
this circuit diagram.
When the voltage reduction caused by the current ( aa
IOUT) which flows through R2 reaches Vbe2 of Tr.2 by
additionally providing the current boost circuit with Tr.2
and R2, Tr.2 is turned ON and the base current of Tr.1 is
increased, so that the output current is limited.
Current limit of Overcurrent Limit Circuit is obtained
as follows :
IOUT Vbe2/R2
*1) Vreg : Set Output Voltage of R×5RE Series.
*1