bq25638 I2C Controlled Battery Charger IC Texas Instruments bq25638 I2C Controlled Battery Charger IC is a highly integrated 5A switch-mode battery charge and system power path management device for single-cell Li-Ion and Li-polymer batteries. The solution is highly integrated with built-in loop compensation, current sensing, input reverse-blocking FET (RBFET, Q1), high-side switching FET (HSFET, Q2), low-side switching FET (LSFET, Q3), and battery FET (BATFET, Q4) between system and battery. It uses NVDC power path management, regulating the system slightly above the battery voltage without dropping below a configurable minimum system voltage. The low-impedance power path reduces battery charging time, optimizes switch-mode operation efficiency, and extends battery life during discharging. The I2C serial interface with the system and charging settings makes bq25638 a truly flexible solution.