1/7

L4909

May 2000

s

3 OUTPUTS

- Vo1 : output voltage variable from 5 to 12 V;

limit current : 1.2 A.

- Vo2 : output voltage variable from 5 to 12 V;

limit current : 1.2 A.

- Vo3 : output voltage variable from 5 to 12 V;

limit current : 1.2 A.

s

ENABLE INPUT FOR EACH REGULATOR

s

FEEDBACK INPUT FOR EACH REGULATOR

s

SHORT CIRCUIT PROTECTION TO GROUND

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OVERCURRENT WARNING

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DRIVER FOR EXTERNAL SCR (CROWBAR

PROTECTION)

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THERMAL SHUTDOWN

DESCRIPTION

It is a monolithic Multifunction Voltage Regulator; it

contains 3 regulators, (REG1, REG2, REG3) each

one with an enable input and a feedback input, to al-

low the voltage setting via external resistive divider.

Each regulator is current limited and furthermore an

OR-ed warning signal is output (open collector, ac-

tive low output) when the current in a regulator goes

above an over-current threshold (1 A typ for any reg-

ulator).

When one output voltage is higher than 20% typ of its

nominal value (for instance in case of input-to-output

short circuit), the crowbar output pin is activated, trig-

gering an external SCR (connected between input

and ground) that blows the input line fuse.

MULTIWATT 15

EXTERNALLY ADJUSTABLE MULTIFUNCTION REGULATOR

BLOCK DIAGRAM

THERMAL

SHUTDOWN

OVER

CURRENT

CHECK

ENABLE

CONTROL

REFERENCE

GENERATOR

REG1

REG1

6

7

9

4

5

8

10

11

15

14

3,13

REF

REF+20%

1

2

EN1

EN2

EN3

TRIG

OC

GND

FB1

FB2

FB3

D00AU1171

REG2

REG3

+

+

+

+

+

+

+

-

+

-

+

-

+

-

+

-

+

-

REG2

REG3