LTC2945

28

Rev. C

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TYPICAL APPLICATIONS

Power Monitoring in –48V System Using External Linear Regulator to Supply Opto-Couplers and SCL/SDA Resistive Pull-Ups

Wide Range Dual Supply Monitor with Single LTC2945

VCC

GND

C1

1µF

PS9817-2

CONTROL REGISTER A2 = 0

VEE

PS9817-2

2945 TA07

ADR0

ADIN

ADR1

SCL

VDD

INTVCC

VEE

SDAI

SDAO

ALERT

SENSE–

GND

SENSE+

LTC2945

LT3010-5

VCC

GND

–48V

RTN

VEE

–48V INPUT

R7

0.5k

R3

0.51k

R4

1k

VOUT

R8

0.51k

R9

1k

R10

1k

R11

10k

5V

5V

RSNS

0.02

VDD

GND

µP

SCL

SDA

INT

R1

1k

R2

10k

IN

SHDN

OUT

SENSE

GND

C3

0.1µF

C2

1µF

* SELECT RSHUNT ACCORDING TO THE EQUATION IN THE “FLEXIBLE POWER SUPPLY TO LTC2945” SECTION.

** VOLTAGE DATA HAS AN OFFSET VALUE DUE TO D1’S DROP, IF DESIRABLE THIS CAN BE COMPENSATED THROUGH SOFTWARE.

RADIN

20k

2945 TA08

RSNS

0.02

C3

0.1µF

C2

0.1µF

ADR0

ADR1

VDD

INTVCC

SDAI

SCL

SDAO

ALERT

ADIN

SENSE+

GND

SENSE–

LTC2945

LTC6102

RIN2

1k

RSHUNT*

D2

BAT54

D1

BAT54

RIN1

1k

C1

0.1µF

RSNS1

0.02

V+

V–

VREG

–INF –INS

OUT

+IN

SUPPLY B

4.5V TO 80V

SUPPLY A

4.5V TO 80V

I2C

INTERFACE

TO

LOAD

SUPPLY A

SENSE+

∆SENSE INTERNALLY GENERATED

USE EXTERNAL µP TO MULTIPLY VOLTAGE (VDD)

AND CURRENT (ADIN) DATA

ADIN

VDD**

1

VOLTAGE

DATA

CURRENT

DATA

POWER

DATA

CONTROL REG

A2

0

SUPPLY B