LTC4450

9

Rev. 0

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Automatic PowerPath™ Control

Figure 4 illustrates an application circuit for automatic

switchover of a load between a battery and a wall adapter.

up by the drain-to-body diode of the LTC4450’s internal

of the battery, the LTC4450 will turn on its power MOSFET,

reducing the IN-to-OUT voltage drop from a diode voltage

to 15mV. Should the wall adapter then be applied, MP1’s

voltage, and the LTC4450 will turn off its power MOSFET.

At the same time, the LTC4450 will sink current into the

STATUS pin, turning on MP1 and reducing the voltage

For wall adapter and/or battery voltages exceeding 5.5V,

a voltage source ranging from 2.75V to 5.5V must be

RCL, DZ1 and MN1 in Figure 5. DCL1 and STAT2 are used

to clamp MP1’s VGS voltage to 5V.

Figure 4. Automatic Switchover of Load Between a Battery and a Wall Adapter with Auxiliary

P-Channel MOSFET In a Low Voltage Application

Figure 5. Automatic Switchover of Load Between a Battery and a Wall Adapter with Auxiliary

P-Channel MOSFET in a High Voltage Application

APPLICATIONS INFORMATION

Si4465DY

47µF

RSTAT1

1k

BATTERY

CELL INPUT

(UP TO 3.7V)

SHDN#

GND

LTC4450

STATUS

IN

OUT

WALL

ADAPTER

INPUT (5V)

MP1

4450 F04

0.1 F

FDS4465

C1

47µF

RSTAT1

1k

RSTAT2

10k

RCL

10k

MN1

2N7002

SHDN#

GND

STATUS

IN

OUT

DCL1

BZX84C5V1L

MP1

DZ1

BZX84C5V1L

4450 F05

BATTERY

INPUT

(7.2V)

WALL

ADAPTER

INPUT (12V)

LTC4450

0.1 F