1FEATURES

23• Supports USB Charging Scheme

• Integrated Pass Transistor

• Near-Depleted Battery Preconditioning

• Monitors Battery Temperature

• Built-In 5.6 Hour Timer

• Under Voltage and Over Voltage Lockout

• Charge Status Indicators

• Charge Current Monitor Analog Output

• LDO Mode Operation can source 1 Amp

• Continuous Over Current/Temperature

Protection

APPLICATIONS

• Cellular Phones

• PDAs

• Digital Cameras

• USB Powered Devices

• Programmable Current Sources

KEY SPECIFICATIONS

• 1% Charger Voltage Accuracy Over

0°C ≤ TJ ≤ 85°C

• 4.3V to 6V Input Voltage Range

• 100 mA to 750 mA Charge Current Range, in

Charger Mode

• 100 mA to 500 mA Charge Current Range, in

USB Mode

• WSON Package Power Dissipation:

2.7W at TA = 25°C

DESCRIPTION

The LP3947 is a complete charge management

system that safely charges and maintains a Li-Ion

battery from either USB power source or AC adaptor.

In USB mode, the LP3947 supports charging in low

power or high power mode. Alternatively, the LP3947

can take charge from AC adaptor. In both USB and AC adaptor modes, charge current, battery regulation

voltage, and End of Charge (EOC) point can be

selected via I2C™ interface. The LP3947 can also

operate on default values that are pre-programmed in

the factory. The battery temperature is monitored

continuously at the Ts pin to safeguard against

hazardous charging conditions. The charger also has

under-voltage and over-voltage protection as well as

an internal 5.6 hr timer to protect the battery. The

pass transistor and charge current sensing resistor

are all integrated inside the LP3947.

The LP3947 operates in four modes: pre-qualification,

constant current, constant voltage and maintenance

modes. There are two open drain outputs for status

indication. An internal amplifier readily converts the

charge current into a voltage. Also, the charger can operate in an LDO mode providing a maximum of 1.2

Amp to the load.