How to design 4.2v lithium battery charging circuit with PT6102?

　　PT6102 is a highly integrated single-cell Li-ion battery charger, and its small number of external components makes it very suitable for portable applications. The internal integrated power tube does not require external detection resistors and anti-backflow diodes.

　　Lithium battery is a type of battery that uses lithium metal or lithium alloy as the negative electrode material and uses a non-aqueous electrolyte solution. The earliest lithium battery came from the great inventor Edison, using the following reaction: Li+MnO2=LiMnO2 This reaction is a redox reaction, discharge. Due to the very active chemical properties of lithium metal, the processing, storage and use of lithium metal have very high environmental requirements. Therefore, lithium batteries have not been used for a long time. Now lithium batteries have become the mainstream.

　　PT6102 is a highly integrated single-cell Li-ion battery charger. The small number of external components makes it very suitable for portable applications. The internal integrated power tube does not require external detection resistors and anti-backflow diodes. The charging current is set by an external resistor, and the charging end voltage is fixed at 4.2V. Thermal feedback can automatically adjust the charging current, and can protect the chip under high power or high ambient temperature. PT6102 charges the current in three stages: when the battery voltage is lower than 2.9V, it is trickle charge, and when the battery voltage is greater than 2.9V When the battery voltage reaches 4.2V, constant voltage charging is performed. During the constant voltage charging process, the charging current gradually decreases, and the trickle charging current is 1/10 of the constant current charging current. When the charging current is 1/10, the charging process ends.