TP4057 is an excellent linear charger with constant current and constant voltage for single lithium ion battery.TP4057 is packaged in SOT23-6 package with less peripheral components, which makes it very suitable for portable products, and suitable for power supply of USB power supply and adapter power supply. 

Based on the special internal MOSFET architecture and anti reverse charging circuit, TP4057 does not need external detection resistor and isolation diode.When the external environment temperature is too high or in high power applications, the thermal feedback can adjust the charging current to reduce the chip temperature.The charging voltage is fixed at 4.24 V, while the charging current can be set externally through a resistor.When the charging current drops to 1 / 10 of the set value after reaching the final floating charge voltage, the chip will terminate the charging cycle. When the input voltage is disconnected,TP4057 will enter sleep state, and the battery leakage current will drop below 1uA.The tp4057 can be set to stop mode, when the static current of the chip drops to 25uA. 

TP4057 also includes other features: battery temperature monitoring, undervoltage locking, automatic recharging and two status pins to show charging and charging termination.