R5RL

• CURRENT BOOST CIRCUIT

 

 

 

 

 

 

 

Tr.1

 

 

 

 

Output current of 60mA or more can be obtained by

 

 

 

 

 

 

 

 

 

 

 

 

 

the current boost circuit constructed as shown in this cir-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

cuit diagram.

 

 

 

 

 

 

 

 

 

VIN

 

 

 

 

VIN

R×5RL

VOUT

 

 

 

 

 

SERIES

 

 

 

 

VOUT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+

 

 

 

 

 

 

+

 

 

 

 

 

C1

 

 

 

 

 

 

GND

 

 

 

C2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

GND

 

 

 

 

 

 

 

 

 

 

 

 

GND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• CURRENT BOOST CIRCUIT WITH OVERCURRENT LIMIT CIRCUIT

R2

Tr.1

 

 

 

Vbe2

 

 

 

 

Tr.2

 

 

 

IOUT

VIN

VIN

R×5RL VOUT

 

 

 

SERIES

 

 

R1

 

 

VOUT

 

 

+

+

 

 

 

C1

 

GND

 

C2

 

 

 

 

GND GND

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 ( 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

• CURRENT SOURCE

 

 

 

 

 

 

 

 

 

 

 

A current source with the structure as shown in this

 

 

 

 

 

 

IOUT

circuit diagram can be used. Output Current IOUT is

 

 

 

 

R×5RL

 

 

VIN

VOUT

 

 

VIN

SERIES

 

 

obtained as follows :

R

 

 

 

 

 

 

 

 

 

*1

/R + ISS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+

GND

 

 

IOUT= Vreg

ISS

 

 

C1

 

 

 

 

Take care that Output Current IOUT does not exceed

 

 

 

 

 

 

 

 

 

 

 

its allowable current.

*1) Vreg : Set Output Voltage of R5RL Series.

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