The LTC4098 LTC4098-1 are high efficiency USB Power-Path controllers and full-featured Li-Ion/Polymer battery chargers. Using the LTC4098 integrated circuit you can make a simple and useful Li-Ion Polymer battery charger , that require few external components and can be used with many power distribution sources like: USB, wall adapter, automotive, Firewire or other high voltage DC/DC converters, and a Li-Ion/Polymer battery.
The LTC4098 LTC4098-1 ‘s internal switching regulator automatically limits its input current for USB compatibility.
For automotive and other high voltage applications, the LTC4098/LTC4098-1 interface with a Linear Technology external switching regulator to provide a high efficiency high voltage power path.
An overvoltage circuit protects the LTC4098 LTC4098-1 from high voltage damage on the USB/wall adaptor inputs with an N-channel FET and a resistor .
Main features of the LTC4098 LTC4098-1 circuits are : switching regulator with bat-track adaptive , output control makes optimal use of limited power available from USB port to charge battery and power application ,overvoltage protection guards against damage , 180mΩ internal ideal diode plus external ideal diode controller seamlessly provide low loss powerpath when input power is limited or unavailable ,preset 4.2V charge voltage with 0.5% accuracy
(4.1V for LTC4098-1) , 4.1V float voltage (LTC4098-1) improves battery life and high temperature safety margin ,instant-On operation with discharged battery , 700mA maximum load current from USB port,1.5A maximum charge current with thermal limiting .