By Monolithic Power Systems 90
MPS’s highly integrated, single-cell, Li-ion/Li-polymer battery chargers with system power path management for space-limited, portable applications. The MP26xx chargers use input power from either an AC adapter or a USB port to supply the system load and charge the battery independently. The charger features trickle charge, constant current (CC) and constant voltage (CV) regulation, charge termination, and charge status.
The power path management function ensures continuous power to the system by automatically selecting the input, the battery, or both to power the system. This power stage features a low dropout regulator from the input to the system and a 100 mΩ switch from the battery to the system. Power path management separates the charging current from the system load, which allows for proper charge termination and keeps the battery in full-charge mode.
The MP26xx provides system short-circuit protection (SCP) by limiting the current from the input to the system and the battery to the system. This feature is especially critical to preventing the Li-ion battery from being damaged by excessively high currents. An on-chip battery undervoltage lockout (UVLO) cuts off the path between the battery and the system if the battery voltage drops below the programmable battery UVLO threshold, which prevents the Li-ion battery from being over-discharged. An integrated I2C control interface allows the MP26xx to program the charging parameters, such as input current limit, input voltage regulation limit, charging current, battery regulation voltage, safety timer, and battery UVLO.