LTC4077

1

4077fa

of charging a single-cell Li-Ion battery from both wall

adapter and USB inputs. The charger can detect power at

the inputs and automatically select the appropriate power

source for charging.

No external sense resistor or blocking diode is required

for charging due to the internal MOSFET architecture.

Internal thermal feedback regulates the battery charge

current to maintain a constant die temperature during high

power operation or high ambient temperature conditions.

The float voltage is fixed at 4.2V and the charge current

is programmed with an external resistor. The LTC4077

terminatesthechargecyclewhenthechargecurrentdrops

below the termination threshold after the final float voltage

is reached. The LTC4077 can be put into shutdown mode

reducing the DCIN supply current to 20µA, the USBIN

supply current to 10µA, and the battery drain current to

less than 2µA even with power applied to both inputs.

Other features include automatic recharge, undervoltage

lockout,chargestatusoutput,powerpresentstatusoutput

to indicate the presence of wall adapter or USB power and

high power/low power adjustable mode for USB compat-

ible applications.

Dual Input Battery Charger for Single-Cell Li-Ion

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

*Protected by U.S. patents, including 6522118

Dual Input Standalone

Li-Ion Battery Charger

TIME (HR)

0

4.2

200

0

400

800

600

1000

1.5

2.5

3.6

3.4

5.0

4.0

3.8

2.5

0

0.5

1.0

2.0

3.0

CONSTANT VOLTAGE

USBIN = 5V

HPWR = 5V

Complete Charge Cycle (1100mAh Battery)

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

■

Charges Single-Cell Li-Ion Batteries from Wall

Adapter and USB Inputs

■

Automatic Input Power Detection and Selection

■

Charge Current Programmable up to 950mA from

Wall Adapter Input

■

C/10 Charge Current Termination

■

Thermal Regulation Maximizes Charge Rate

Without Risk of Overheating*

■

Preset Charge Voltage with ±0.6% Accuracy

■

18µA USB Suspend Current in Shutdown

■

Power Present Status Output

■

Charge Status Output

■

Automatic Recharge

■

Available in a Thermally Enhanced, Low Profile

(0.75mm) 10-Lead (3mm × 3mm) DFN Package

■

Cellular Telephones

■

Handheld Computers

■

Portable MP3 Players

■

Digital Cameras

LTC4077

DCIN

USBIN

IUSB

IDC

BAT

HPWR

IUSBL

1.24k

1%

2k

1%

2k

1%

WALL

ADAPTER

USB

PORT

1 F

1 F

4.2V

SINGLE CELL

Li-Ion BATTERY

800mA (WALL)

500mA (USB)

4077 TA01

GND

+