MP2639-2 string lithium charging and discharging scheme

Chip Solution Battery Power Management Chip MP2639AGR-Z

The input is the TYPEC interface, which is also used for output.

2-cell Li-ion or Li-Polymer switching charger 5V input compatible and integrated bi-directional charge/discharge 2.5A

The MP2639A is a highly integrated, flexible switch-mode battery charge management device for 2-cell series Li-ion and Li-polymer battery packs used in a variety of portable applications.

The MP2639A is capable of charging from 5V to a 2-cell battery adapter or USB input. 

In a 2-cell application, the 5V input charges the 2-cell battery in boost mode operation through the MP2639A.

When the 5V input is missing, the 2-cell battery voltage is discharged through the transistor to the 5V output MP2639A operates in buck mode.

For charging functions in each application, the MP2639A automatically detects the battery voltage and charges the battery in three phases: trickle current, constant current and constant voltage.

Other features include charge termination and automatic top-up.

To ensure safe operation, the MP2639A limits the chip temperature to a preset value of 120oC.

Other safety features include input overvoltage protection, battery overvoltage protection, thermal shutdown, battery temperature monitoring and a programmable timer to prevent the battery from being charged for extended periods of time.