LTC4096X View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LTC4096X

Dual Input Standalone Li-Ion Battery Chargers

Linear Technology 

LTC4096/LTC4096X

OPERATION

The LTC4096 is designed to efficiently manage charging a

single-cell lithium-ion battery from two separate voltage

sources: a wall adapter and USB power bus. Using the

constant-current/constant-voltage algorithm, the charger

can deliver up to 1.2A of charge current from the wall

adapter supply or up to 1A of charge current from the

USB supply with a final float voltage accuracy of ±0.6%.

The LTC4096 has two internal P-channel power MOSFETs,

thermal regulation and shut down circuitry. No blocking

diodes or external sense resistors are required.

Power Source Selection

The LTC4096 can charge a battery from either the wall

adapter input or the USB port input. The LTC4096 automati-

cally senses the presence of voltage at each input. If both

voltage sources are present, the LTC4096 defaults to the

wall adapter source provided sufficient voltage is present

at the DCIN input. “Sufficient voltage” is defined as:

• Supply voltage is greater than the UVLO threshold.

• Supply voltage is greater than the battery voltage by

30mV (100mV or 150mV rising, 30mV falling).

The power present output pin (PWR) indicates that suf-

ficient input voltage is available. Table 1 describes the

behavior of this status output.

Programming and Monitoring Charge Current

The charge current delivered to the battery from the wall

adapter supply is programmed using a single resistor from

the IDC pin to ground.

RIDC

=

1000V

ICHRG(DC)

,

ICHRG(DC)

=

1000V

RIDC

Similarly, the charge current from the USB supply is

programmed using a single resistor from the IUSB pin

to ground.

1000V

1000V

RIUSB = ICHRG(USB) , ICHRG(USB) = RIUSB

Charge current out of the BAT pin can be determined at

any time by monitoring the IDC or IUSB pin voltage and

applying the following equations:

IBAT

=

VIDC

RIDC

• 1000, (charging

from

wall

adapter)

IBAT

=

VIUSB

RIUSB

•

1000, (charging

from USBsupply)

Table 1. Power Source Selection

VDCIN > 4.2V and

VDCIN > BAT + 30mV

VDCIN < 4.2V or

VDCIN < BAT + 30mV

VUSBIN > 4V and

VUSBIN > BAT + 30mV

Charger powered from wall adapter source;

VPWR = VDCIN – RDC-PWR • IPWR

USBIN current < 25µA

VUSBIN < 4V or

VUSBIN < BAT + 30mV

Charger powered from wall adapter source

VPWR = VDCIN – RDC-PWR • IPWR

Charger powered from USB source;

VPWR = VUSBIN – RUSB-PWR • IPWR

No charging

PWR: Hi-Z

4096xf

9

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