Battery-charger controller
ON Semiconductor

NCP1835B is an integrated linear charger specifically designed to charge 1-cell Li-Ion batteries with a constant current, constant voltage (CCCV) profile.
Its low input voltage capability, adjustable charge current, ability to maintain regulation without a battery, and its onboard thermal foldback make it versatile enough to charge from a variety of wall adapters. The NCP1835B can charge from a standard wall adapter or from the USB port. It has been optimized to charge low capacity batteries such as those found in wireless headsets and flash memory-based MP3 players. The recommended charge current rate is 30-300 mA.
Features

* Integrated Voltage and Current Regulation
* No External MOSFET, Sense Resistor or Blocking Diode Required
* Charge Current Thermal Foldback
* Integrated Precharge Current for Conditioning a Deeply Discharged Battery
* Integrated End of Charge (EOC) Detection
* 1% Voltage Regulation
* 4.2 V Regulated Output Voltage
* Regulation Maintained without a Battery Present
* Programmable Full Charge Current
* Open Drain Charge Status and Fault Alert Flags
* 2.8 V Output for AC Present Indication and Powering Charging Subsystems
* Minimum Input Voltage of 2.4 V Allows Use of Current Limited Adapters
* Automatically Recharging if Battery Voltage Drops after Charging Cycle is Completed
* Battery Powered Devices
* Pb-Free Package is Available

Applications

* Wireless Headsets
* Bluetooth Devices
* MP3 Players
* USB Appliances