R×5RE
• CURRENT BOOST CIRCUIT
Output current of 120mA or more can be obtained
by the current boost circuit constructed as shown in
this circuit diagram.
Tr.1
VIN
VOUT
R×5RE
SERIES
VIN
VOUT
GND
+
+
C1
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
this circuit diagram.
Tr.1
R2
Vbe2
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 :
Tr.2
IOUT
VIN
VOUT
R×5RE
SERIES
VIN
R1
VOUT
+
+
C2
GND
GND
GND
IOUT
Vbe2/R2
• 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
VIN
VOUT
R×5RE
SERIES
VIN
1
*
R
IOUT=Vreg /R + ISS
GND
+
Take care that Output Current IOUT does not exceed
its allowable current.
ISS
C1
1) Vreg : Set Output Voltage of R×5RE Series.
*
19
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
