DESCRIPTION
The SUM9510 is a single cell, fully integrated constant current (CC)/constant voltage (CV) Li-ion battery charger.
Its compact package with minimum external components requirement makes the SUM9510 ideal for portable applications. No external sense resistor or blocking diode is necessary for the SUM9510. Build-in thermal feedback mechanism regulates the charge current to control the die temperature during high power operation or at elevated ambient temperature.
The SUM9510 has a pre-charge function for trickle charging deeply discharged batteries. The fast charge current can be programmed by an external resistor. CV regulation mode is automatically enabled once the battery’s charging curve reaches the constant voltage portion. The output current then decays and is finally terminated once the charge current drops to 1/10 of the programmed value. The SUM9510 keeps monitoring the battery voltage and enables a new charge cycle once the voltage drops by 150mV below the CV value. Power supply state is constantly monitored and the battery drain current is reduced to minimum value automatically when the SUM9510 senses a lack of input power. A status pin outputs a logic HIGH/LOW to indicate the charging status and the presence of power supply. Integrated with constant current control technology, SUM9510's indicator pin can ensure the indicator brightness stability without external current limiting resistor.
Other features include charge current monitor, under-voltage lockout. 

FEATURES

 Standalone Capability with no Requirement of External MOSFET, Sense Resistor or Blocking Diode.
 Complete Linear Charger in Compact Package for Single Cell Lithium-Ion Batteries
 Programmable Pre-charge, Fast Charge and Termination Current.
 Constant-Current/Constant-Voltage Operation with Thermal Regulation to Maximize Charge Rate Without Risk of Overheating
 Charges Single Cell Li-Ion Batteries Directly from USB Port
 Preset 4.24V Charge Voltage maximum.
 Automatic Recharge
 Charge Status Output Pin
 C/10 Charge Termination
 Soft-Start Limits Inrush Current
 Available in SOT23-5 and TSOT23-5 Package
 Constant current function without LED current limiting resistor.

http://www.sumsemi.com/