10

LTC4413

4413f

APPLICATIO S I FOR ATIO

Figure 5

Figure 3

Figure 4

LTC4413

IDEAL

ENBA

2

4

3,11

1

5

10

9

6

ENBB

STAT

GND

INA

OUTA

BATA

1-CELL Li-Ion

R1

1000k

R2

200k

470k

C1:C1206C106K8PAC

C2:C1206C475K8PAC

C2

4.7µF

4413 F03

TO

LOAD

WALL

ADAPTER

C1

10µF

MP1 FDR8508

IDEAL

INB

OUTB

BATB

1-CELL Li-Ion

LTC4413

IDEAL

ENBA

2

4

3,11

1

5

10

9

6

ENBB

STAT

STAT

GND

INA

OUTA

470k

C1

4.7µF

4413 F04

TO

LOAD

PRIMARY

POWER

AUX

POWER

IDEAL

INB

OUTB

10µF

10µF

MICROCONTROLLER

microcontroller’s analog inputs (perhaps with the aid of a

resistor voltage divider) monitors each supply input and

the LTC4413 status, and then commands the LTC4413

through the two ENBA/ENBB control inputs.

Automatic Switchover from a Battery to an Auxiliary

Supply or a Wall Adapter

Figure 5 illustrates an application for implementing the

function of automatic switchover from a battery to either

an auxiliary supply or to a wall adapter using the LTC4413.

The LTC4413 automatically senses the presence of a wall

adapter as the ENBB pin voltage is pulled higher than its

rising turn-off threshold of 550mV through resistive di-

vider (R4 and R5). This disables the AUX input from

powering the load. If the AUX is not present when a wall

adapter is attached (i.e., the BAT is supplying load cur-

rent), as the wall adapter voltage rises, the body diode in

MP1 will forward bias, pulling the output voltage above the

BAT voltage. The LTC4413 will sense a reverse voltage of

as little as 10mV and turn off the ideal diode between INA

and OUTA. This will cause the STAT voltage to fall, turning

on MP1. The load will then draw current from the wall

adapter, and the battery will be disconnected from the

load. If the AUX is not present when the wall adapter is

removed, the load voltage will droop until the BAT voltage

exceeds the load voltage. The LTC4413 will sense that the

BAT voltage is greater, causing the STAT voltage to rise,

disabling MP1; the BAT will then provide power to the load.

LTC4413

IDEAL

ENBB

4

ENBA

2

3,11

1

5

10

9

6

STAT

GND

INA

OUTA

R2

1000k

R3

100k

BAT

470k

C1:C0805C106K8PAC

C2:C1206C475K8PAC

C2

4.7µF

4413 F05

TO

LOAD

WALL

ADAPTER

AUX

ADAPTER

R4

1000k

R5

500k

R1

1Ω

C1

10µF

MP1 FDR8508

IDEAL

INB

OUTB

current to the load. When a wall adapter input is applied,

the voltage divider formed by R1 and R2 will disable the

LTC4413, causing the STAT pin voltage to fall, turning on

MP1. At this point the load will be powered by the wall

adapter and both batteries may be removed without inter-

rupting the load voltage. When the wall adapter is re-

moved, the output voltage will droop until the voltage

divider turns on the LTC4413, at which point the batteries

will revert to providing load power. The status signal can

also be used to provide information as to whether the wall

adapter (or BATB) is supplying the load current.

Automatic PowerPath Control

Figure 4 illustrates an application circuit for microcontrol-

ler monitoring and control of two power sources. The