LP3947 Datasheet | National Semiconductor

Description The LP3947 is a plete 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. n n n n n n n n 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 Key Specifications n 1% Charger Voltage Accuracy Over 0˚C ≤ TJ ≤ 85˚C n 4.3V to 6.0V Input Voltage Range n 100 m A to 750 m A charge current range, in charger mode n 100m A to 500m A charge current range, in USB mode n LLP Package Power Dissipation: 2.7W at TA = 25˚C Applications n n n n n Cellular Phones PDAs Digital Cameras USB Powered Devices Programmable Current Sources Features n Supports USB Charging Scheme n Integrated Pass Transistor Typical Application Circuit More Application Circuit can be found in...