Low Iq highly integrated battery charge management solution

The BQ25121A, from Texas Instruments, is a highly integrated battery charge management IC that integrates the most common functions for wearable devices: Linear charger, regulated output, load switch, manual reset with timer, and battery voltage monitor. The integrated buck converter is a high efficiency, low IQ switcher using DCS-Control that increases light load efficiency down to 10µA load currents. The low quiescent current during operation and shutdown allows maximum battery life. The device supports charge currents from 5mA to 300mA. The input current limit, buck converter output voltage, charge current, LDO output voltage, and other parameters are programmable through the I2C interface. Battery charging uses a standard Li-Ion charge profile with three phases: precharge, constant current and constant voltage. A voltage-based JEITA compatible battery pack thermistor monitoring input (TS) is incorporated that monitors battery temperature and automatically changes charge parameters to stop the battery from charging outside of its safe temperature range. The charger is optimised for 5V USB input, with 20V tolerance to withstand line transients. The buck converter is run from the input or battery. When in battery-only mode, the device can run from a battery up to 4.65V. A configurable load switch allows system optimization by disconnecting infrequently used devices. The manual reset with timer allows multiple different configuration options for wake are reset optimisation. A simple voltage based monitor provides battery level information to the host in 2% increments from 60% to 100% of the programmed V(BATREG).