RICOH RH5RE47AA-RR

VOLTAGE REGULATOR
FOR MIDDLE OUTPUT CURRENT
R×5RE SERIES
APPLICATION MANUAL
NO.EA-016-0006
VOLTAGE REGULATOR
FOR MIDDLE OUTPUT CURRENT
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 constant 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.
FEATURES
• 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)
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
VIN
VOUT
2
3
+
–
Vref
1
GND
1
R × 5RE
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.
a
b cd
}
↑
}
R × 5RE ×××× –×× ← Part Number
↑ ↑↑ ↑
e
Code
Contents
a
Designation of Package Type:
E: TO-92
H: SOT-89 (Mini-power Mold)
b
Setting Output Voltage (VOUT):
Stepwise setting with a step of 0.1V in the range of 2.0V to 6.0V is possible.
c
A
d
Designation of Packing Type:
A: Taping
C: Antistatic bag for TO-92 and samples
e
Designation of Taping Type:
Ex. TO-92 : RF, RR, TZ
SOT-89: T1, T2
(refer to Taping Specifications)
“TZ” and “T1” are prescribed as a standard.
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.
2
R × 5RE
PIN CONFIGURATION
• TO-92
• SOT-89
(mark side)
(mark side)
1
1
2
2
3
3
PIN DESCRIPTION
• TO-92
• SOT-89
Pin No.
Symbol
Pin No.
Symbol
1
GND
1
GND
2
VIN
2
VIN
3
VOUT
3
VOUT
3
R × 5RE
ABSOLUTE MAXIMUM RATINGS
Symbol
VIN
Item
Input Voltage
Rating
Unit
+12
V
VOUT
Output Voltage
–0.3 to VIN+0.3
V
IOUT
Output Current
300
mA
Power Dissipation
300
mW
PD
Topt
Operating Temperature
–40 to +85
˚C
Tstg
Storage Temperature
–55 to +25
˚C
Lead Temperature (Soldering)
260˚C, 10s
Tsolder
ABSOLUTE MAXIMUM RATINGS
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.
4
R × 5RE
ELECTRICAL CHARACTERISTICS
Topt=25˚C
Symbol
Item
Conditions
MIN.
TYP.
MAX.
Unit
2.050
V
VOUT
Output Voltage
VIN=4.0V,IOUT=10mA
1.950
2.000
IOUT
Output Current
VIN=4.0V
40
60
∆VOUT
∆IOUT
VDIF
ISS
∆VOUT
Load Regulation
Dropout Voltage
Quiescent Current
∆VIN
Line Regulation
VIN
Input Voltage
Ilim
Current Limit
∆VOUT
∆Topt
Output Voltage
Temperature Coefficient
VIN=4.0V
mA
1mA≤IOUT≤50mA
40
80
mV
IOUT=30mA
0.5
0.7
V
VIN=4.0V
1.0
3.0
µA
IOUT=10mA
0.1
VOUT+1.0V≤VIN≤10V
%/V
10
IOUT=10mA
–40˚C≤Topt≤85˚C
240
mA
±100
ppm/˚C
• R × 5RE30A
Symbol
Topt=25˚C
Item
Conditions
MIN.
TYP.
MAX.
Unit
3.075
V
VOUT
Output Voltage
VIN=5.0V,IOUT=10mA
2.925
3.000
IOUT
Output Current
VIN=5.0V
50
80
∆VOUT
∆IOUT
VDIF
ISS
∆VOUT
Load Regulation
Dropout Voltage
Quiescent Current
∆VIN
Line Regulation
VIN
Input Voltage
Ilim
Current Limit
∆VOUT
∆Topt
V
Output Voltage
Temperature Coefficient
VIN=5.0V
mA
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
IOUT=10mA
–40˚C≤Topt≤85˚C
V
240
mA
±100
ppm/˚C
5
R × 5RE
• R × 5RE40A
Symbol
Topt=25˚C
Item
Conditions
MIN.
TYP.
MAX.
Unit
4.100
V
VOUT
Output Voltage
VIN=6.0V,IOUT=10mA
3.900
4.000
IOUT
Output Current
VIN=6.0V
65
100
∆VOUT
∆IOUT
VDIF
ISS
∆VOUT
Load Regulation
Dropout Voltage
Quiescent Current
∆VIN
Line Regulation
VIN
Input Voltage
Ilim
Current Limit
∆VOUT
∆Topt
Output Voltage
Temperature Coefficient
VIN=6.0V
mA
1mA≤IOUT≤70mA
40
80
mV
IOUT=50mA
0.5
0.7
V
VIN=6.0V
1.2
3.6
µA
IOUT=10mA
0.1
VOUT+1.0V≤VIN≤10V
%/V
10
IOUT=10mA
–40˚C≤Topt≤85˚C
240
mA
±100
ppm/˚C
• R × 5RE50A
Symbol
Item
Conditions
MIN.
TYP.
MAX.
Unit
5.125
V
Output Voltage
VIN=7.0V,IOUT=10mA
4.875
5.000
IOUT
Output Current
VIN=7.0V
80
120
∆IOUT
VDIF
ISS
∆VOUT
Load Regulation
Dropout Voltage
Quiescent Current
∆VIN
Line Regulation
VIN
Input Voltage
Ilim
Current Limit
∆VOUT
∆Topt
6
Topt=25˚C
VOUT
∆VOUT
V
Output Voltage
Temperature Coefficient
VIN=7.0V
mA
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
IOUT=10mA
–40˚C≤Topt≤85˚C
V
240
mA
±100
ppm/˚C
R × 5RE
• R × 5RE60A
Symbol
Topt=25˚C
Item
Conditions
MIN.
TYP.
MAX.
Unit
6.150
V
VOUT
Output Voltage
VIN=8.0V,IOUT=10mA
5.850
6.000
IOUT
Output Current
VIN=8.0V
80
120
∆VOUT
∆IOUT
VDIF
ISS
∆VOUT
Load Regulation
Dropout Voltage
Quiescent Current
∆VIN
Line Regulation
VIN
Input Voltage
Ilim
Current Limit
∆VOUT
∆Topt
Output Voltage
Temperature Coefficient
VIN=8.0V
mA
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
IOUT=10mA
–40˚C≤Topt≤85˚C
V
240
mA
±100
ppm/˚C
7
R × 5RE
ELECTRICAL CHARACTERISTICS BY OUTPUT VOLTAGE
Output Voltage
VOUT(V)
Part Number
Conditions
R × 5RE20A
R × 5RE21A
R × 5RE22A
R × 5RE23A
R × 5RE24A
R × 5RE25A
R × 5RE26A
R × 5RE27A
R × 5RE28A
R × 5RE29A
R × 5RE30A
R × 5RE31A
R × 5RE32A
R × 5RE33A
R × 5RE34A
R × 5RE35A
R × 5RE36A
R × 5RE37A
R × 5RE38A
R × 5RE39A
R × 5RE40A
R × 5RE41A
R × 5RE42A
R × 5RE43A
R × 5RE44A
R × 5RE45A
R × 5RE46A
R × 5RE47A
R × 5RE48A
R × 5RE49A
R × 5RE50A
R × 5RE51A
R × 5RE52A
R × 5RE53A
R × 5RE54A
R × 5RE55A
R × 5RE56A
R × 5RE57A
R × 5RE58A
R × 5RE59A
R × 5RE60A
8
OutputCurrent
MIN.
1.950
2.048
2.145
2.243
2.340
2.438
2.535
2.633
2.730
2.828
2.925
3.023
3.120
3.218
3.315
3.413
VIN– 3.510
VOUT 3.608
=2.0V 3.705
3.803
3.900
3.998
IOUT
4.095
=10mA 4.193
4.290
4.388
4.485
4.583
4.680
4.778
4.875
4.973
5.070
5.168
5.265
5.363
5.460
5.558
5.655
5.753
5.850
IOUT(mA)
TYP.
MAX.
2.000
2.100
2.200
2.300
2.400
2.500
2.600
2.700
2.800
2.900
3.000
3.100
3.200
3.300
3.400
3.500
3.600
3.700
3.800
3.900
4.000
4.100
4.200
4.300
4.400
4.500
4.600
4.700
4.800
4.900
5.000
5.100
5.200
5.300
5.400
5.500
5.600
5.700
5.800
5.900
6.000
2.050
2.152
2.255
2.357
2.460
2.562
2.665
2.767
2.870
2.972
3.075
3.177
3.280
3.382
3.485
3.587
3.690
3.792
3.895
3.997
4.100
4.202
4.305
4.407
4.510
4.612
4.715
4.817
4.920
5.022
5.125
5.227
5.330
5.432
5.535
5.637
5.740
5.842
5.945
6.047
6.150
Conditions
MIN.
TYP.
Load Regulation
Dropout Voltage
∆VOUT/∆IOUT(mV)
VDIF(V)
Conditions
TYP.
MAX.
Conditions
TYP.
MAX.
0.5
0.7
VIN–
VOUT
=2.0V
40
60
1mA≤
IOUT
≤50mA
IOUT
=30mA
VIN–
VOUT
=2.0V
1mA≤
IOUT
≤60mA
50
IOUT
80
=40mA
VIN–
VIN–
VOUT
VOUT
=2.0V
=2.0V
40
80
1mA≤
IOUT
≤70mA
65
IOUT
100
=50mA
VIN–
VOUT
=2.0V
80
120
1mA≤
IOUT
IOUT
=60mA
≤80mA
R × 5RE
Topt=25˚C
Quiescent Current
∆VOUT/∆VI N(%/V) VI N(V) Ilim(mA) ∆VOUT/∆T(ppm/˚C)
Iss(µA)
Conditions
Line Regulation Input Voltage Current Limit Output Voltage Tempco.
TYP.
MAX.
1.0
3.0
1.1
3.3
Conditions
TYP.
MAX.
TYP.
Conditions
TYP.
IOUT
=10mA
VIN–
VOUT
IOUT
=10mA
1.2
3.6
=2.0V
0.1
VOUT+
10
240
±100
–40˚C≤
1.0V≤
Topt
VIN
≤85˚C
≤10V
1.3
3.9
1.4
4.2
9
R × 5RE
OPERATION
Output Voltage VOUT divided at the node between
VOUT
VIN
Registers R1 and R2 is compared with Reference Voltage
by Error Amplifier, so that a constant voltage is output.
Error Amplifire
–
R1
+
Vref
R2
GND
GND
FIG. 1 Brock Diagram
TEST CIRCUITS
VIN
VIN
CI
1µF
+
R×5RE
SERIES
VOUT
ISS
IOUT
VOUT
P.G
R×5RE
SERIES
VOUT
GND
VOUT
+
Ro
Co
0.1µF
FIG. 4 Line Transient Response Test Circuit
10
R×5RE
SERIES
VOUT
GND
FIG. 3 Quiescent Current Test Circuit
FIG. 2 Test Circuit
VIN
VIN
CI +
1µF
+ Co
1µF
GND
VIN
R × 5RE
TYPICAL CHARACTERISTICS
1) Output Voltage vs. Output Current
R × 5RE30A
3.1
R × 5RE40A
VIN=5.0V
VIN=6.0V
4.1
Output Voltage VOUT(V)
Output Voltage VOUT(V)
Topt= –40˚C
3.0
25˚C
2.9
85˚C
2.8
Topt=–40˚C
4.0
25˚C
3.9
3.8
85˚C
2.7
3.7
0
50
100
150
200
Output Current IOUT(mA)
R × 5RE50A
5.1
250
0
150
50
100
Output Current IOUT(mA)
R × 5RE50A
VIN=7.0V
200
VIN=7.0V
5.1
5.0
25˚C
4.9
85˚C
4.8
Output Voltage VOUT(V)
Output Voltage VOUT(V)
Topt=–40˚C
5.0
with heatsink
4.9
without heatsink
4.8
heatsink
30×30×1mm
4.7
4.7
0
50 100 150 200 250 300 350
Output Current IOUT(mA)
0
50
100
150
200
Output Current IOUT(mA)
250
2) Output Voltage vs. Input Voltage
IOUT=1µA
2.0
1.8
1.6
10mA
1.4
1.2
1.0
0.8
1.0
1mA
Topt=25˚C
2.04
Output Voltage VOUT(V)
Output Voltage VOUT(V)
2.2
R × 5RE20A
Topt=25˚C
2.4
2.02
IOUT=1µA
2.00
1mA
10mA
1.98
1.96
2.0
3.0
4.0
Input Voltage VIN(V)
5.0
2
3
4
5
6
Input Voltage VIN(V)
7
11
R × 5RE
R × 5RE30A
3.4
R × 5RE30A
Topt=25˚C
Topt=25˚C
3.00
IOUT=1mA
2.8
2.6
50mA
2.4
2.2
10mA
2.0
1.8
2.0
2.5
3.0
3.5
4.0
Input Voltage VIN(V)
R × 5RE40A
4.2
Output Voltage VOUT(V)
Output Voltage VOUT(V)
3.0
2.99
IOUT=1µA
2.98
1mA
2.97
10mA
2.96
2.95
3.0
4.5
4.0
5.0
6.0
7.0
Input Voltage VIN(V)
R × 5RE40A
Topt=25˚C
8.0
Topt=25˚C
4.06
4.0
Output Voltage VOUT(V)
Output Voltage VOUT(V)
3.2
IOUT=1mA
3.8
3.6
50mA
3.4
4.04
4.02
IOUT=1µA
4.00
1mA
10mA
3.98
10mA
3.96
3.5
4.5
5.5
Input Voltage VIN(V)
R × 5RE50A
Output Voltage VOUT(V)
5.1
5.0
4.8
4.6
IOUT=1mA
10mA
50mA
5
6
7
8
Input Voltage VIN(V)
R × 5RE50A
Topt=25˚C
4.4
4.2
4.0
12
4
5.05
5.04
Output Voltage VOUT(V)
3.2
2.5
9
Topt=25˚C
5.03
5.02
5.01
IOUT=1µA
5.00
4.99
4.98
1mA 10mA
4.97
4.96
4.95
4.5
5.0
5.5
6.0
Input Voltage VIN(V)
6.5
5
6
7
8
9
Input Voltage VIN(V)
10
R × 5RE
3) Dropout Voltage vs. Output Curret
R × 5RE30A
R × 5RE40A
1.0
1.2
Dropout Voltage VDIF(V)
Dropout Voltage VDIF(V)
1.4
85˚C
1.0
0.8
25˚C
0.6
0.4
0.2
0.8
85˚C
0.6
25˚C
0.4
0.2
Topt=–40˚C
Topt=–40˚C
0.0
0.0
0
20
40
60
80
Output Current IOUT(mA)
0
100
20
40
60
80
Output Current IOUT(mA)
100
R × 5RE50A
0.8
Dropout Voltage VDIF(V)
0.7
0.6
85˚C
0.5
25˚C
0.4
0.3
0.2
Topt= –40˚C
0.1
0.0
0
20
40
60
80
Output Current IOUT(mA)
100
4) Output Voltage vs.Temperature
Output Voltage VOUT(V)
3.1
R × 5RE40A
IOUT=10mA
3.0
2.9
-50 -30 -10 10 30 50 70
Temperature Topt(˚C)
4.1
Output Voltage VOUT(V)
R × 5RE30A
90
IOUT=10mA
4.0
3.9
-50 -30 -10 10 30 50 70
Temperature Topt(˚C)
90
13
R × 5RE
R × 5RE50A
Output Voltage VOUT(V)
5.2
IOUT=10mA
5.1
5.0
4.9
4.8
-50 -30 -10 10 30 50 70
Temperature Topt(˚C)
90
5) Quiescent Current vs. Input Voltage
R × 5RE20A
R × 5RE30A
Topt=25˚C
1.4
Quiescent Current Iss(µA)
Quiescent Current Iss(µA)
1.1
1.0
0.9
0.8
0.7
Topt=25˚C
1.3
1.2
1.1
1.0
0.6
3
4
5
6
7
8
Input Voltage VIN(V)
R × 5RE40A
1.5
9
10
2
3
4
5 6
7 8
Input Voltage VIN(V)
R × 5RE50A
Topt=25˚C
1.5
9
10
Topt=25˚C
Quiescent Current Iss(µA)
Quiescent Current Iss(µA)
1.4
1.4
1.3
1.2
1.1
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
1.0
14
4
5
6
7
8
9 10
Input Voltage VIN(V)
11
0.5
5
6
7
8
9 10 11
Input Voltage VIN(V)
12
R × 5RE
6) Quiescent Current vs. Temperature
R × 5RE20A
1.6
Quiescent Current Iss(µA)
Quiescent Current Iss(µA)
1.5
1.3
1.1
0.9
0.7
0.5
–40 –20
R × 5RE40A
1.2
1.0
0 20 40 60 80 100
Temperature Topt(˚C)
R × 5RE50A
VIN=6.0V
VIN=5.0V
1.4
0.8
–40 –20
0 20 40 60 80 100
Temperature Topt(˚C)
1.7
1.5
VIN=7.0V
1.4
1.5
Quiescent Current Iss(µA)
Quiescent Current Iss(µA)
R × 5RE30A
VIN=4.0V
1.7
1.3
1.1
0.9
0.7
0.5
–40 –20
0 20 40 60 80 100
Temperature Topt(˚C)
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
–40 –20
0 20 40 60 80 100
Temperature Topt(˚C)
7) Dropout Voltage vs. Set Output Voltage
R × 5RE SERIES Topt=25˚C
Dropout Voltage VDIF(V)
0.7
0.6
0.5
IOUT=50mA
0.4
0.3
0.2
10mA
0.1
1mA
0.0
0
1
2
3
4
5
Set Output Voltage Vreg(V)
6
15
R × 5RE
4.5
Input Voltage
3.5
3.0
2.5
Output Voltage
2.0
1.5
2.0
2.5 3.0 3.5
Time t(ms)
R × 5RE40A
8.0
Input Voltage/Output Voltage V(V)
Input Voltage/Output Voltage V(V)
4.5
1.0
1.5
4.0
6.0
5.0
Output Voltage
4.0
3.0
2.0
2.5 3.0 3.5
Time t(ms)
4.0
6.0
5.0
Input Voltage
4.0
Output Voltage
3.0
2.0
2.0
2.5 3.0 3.5
Time t(ms)
R × 5RE50A
IOUT=1mA
Input Voltage
IOUT=1mA
7.0
1.0
1.5
4.5
7.0
2.0
1.5
R × 5RE30A
IOUT=1mA
5.0
4.5
8.0
7.0
Input Voltage
6.0
Output Voltage
5.0
4.0
3.0
0
4.5
4.0
IOUT=1mA
9.0
Input Voltage/Output Voltage V(V)
Input Voltage/Output Voltage V(V)
8) Line Transient Response (1)
R × 5RE20A
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time t(ms)
9) Line Transient Response (2)
4.5
4.0
3.5
3.0
Output Voltage
2.0
1.5
1.0
0.5
0.0
1.5
16
Input Voltage
2.5
2.0
R × 5RE30A
IOUT=30mA
Input Voltage/Output Voltage V(V)
Input Voltage/Output Voltage V(V)
R × 5RE20A
5.0
2.5 3.0 3.5
Time t(ms)
4.0
4.5
7.0
IOUT=30mA
6.0
5.0
Input Voltage
4.0
Output Voltage
3.0
2.0
1.0
1.5
2.0
2.5 3.0 3.5
Time t(ms)
4.0
4.5
R × 5RE
IOUT=30mA
7.0
Input Voltage
6.0
5.0
Output Voltage
4.0
3.0
2.0
1.5
2.0
2.5 3.0 3.5
Time t(ms)
9.0
Input Voltage/Output Voltage V(V)
Input Voltage/Output Voltage V(V)
R × 5RE40A
8.0
4.0
4.5
R × 5RE50A
IOUT=30mA
8.0
7.0
Input Voltage
6.0
Output Voltage
5.0
4.0
3.0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time t(ms)
17
R × 5RE
TYPICAL APPLICATION
In R × 5RE Series, a constant voltage can be obtained
VIN
VIN
C1
+
R×5RE
SERIES
without using Capacitors C1 and C2. However, when the
VOUT
+
VOUT
wire connected to VIN is long, use Capacitor C1. Output
noise can be reduced by using Capacitor C2.
C2
GND
Insert Capacitors C1 and C2 with the capacitance of
0.1µF to 2.0µF between Input/Output Pins and GND Pin
GND
GND
with minimum wiring.
APPLICATION CIRCUITS
• VOLTAGE BOOST CIRCUIT
The output voltage can be obtained by the following formula :
VIN
VIN
R×5RE
SERIES
VOUT
VOUT
+
GND
C1
Since the quiescent current of R × 5RE Series is so
C2
R1
small that the resistances of R1 and R2 can be set as
ISS
+
1
VOUT=Vreg* · (1+R2/R1) + ISS · R2
large as several hundreds kΩ and therefore the sup-
GND
ply current of “Voltage Boost Circuit” itself can be
R2
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.
*1) Vreg : Set Output Voltage of R×5RE Series.
• DUAL POWER SUPPLY CIRCUIT
As shown in the circuit diagram, a dual power supply circuit can be constructed by using two R × 5RE
IC1
VIN
VIN
R×5RE20A
VOUT
C1
VOUT1
5V
+
This circuit diagram shows a dual power supply
D
ISS
GND
circuit with an output of 3V and an output of 5V.
IC2
VIN
C2
R×5RE30A
+
VOUT
C3
VOUT2
3V
+
R
18
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
GND
GND
Series.
GND
becomes larger than VOUT1.
R × 5RE
• CURRENT BOOST CIRCUIT
Output current of 120mA or more can be obtained
Tr.1
by the current boost circuit constructed as shown in
this circuit diagram.
R×5RE
SERIES
VIN
VIN
C1
VOUT
VOUT
+
+
GND
C2
GND
GND
• CURRENT BOOST CIRCUIT WITH OVERCURRENT LIMIT CIRCUIT
A circuit for protecting Tr.1 from the destruction
caused by output short-circuit or overcurrent is shown in
Tr.1
R2
this circuit diagram.
Vbe2
When the voltage reduction caused by the current ( aa
Tr.2
IOUT
R×5RE
SERIES
VIN
VIN
+
R1
VOUT
+
GND
VOUT
C2
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.
GND
GND
Current limit of Overcurrent Limit Circuit is obtained
as follows :
IOUT
Vbe2/R2
• CURRENT SOURCE
A current source with the structure as shown in
VIN
VIN
C1
+
R×5RE
SERIES
GND
IOUT
VOUT
R
ISS
this circuit diagram can be used. Output Current
IOUT is obtained as follows :
1
IOUT=Vreg* /R + ISS
Take care that Output Current IOUT does not exceed
its allowable current.
*1) Vreg : Set Output Voltage of R×5RE Series.
19