The bq2512x 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 extends light load efficiency down to
10-µA load currents. The low quiescent current during operation and shutdown enables maximum
battery life. The device supports charge currents from 5 mA to 300 mA. The input current limit,
charge current, buck converter output voltage, LDO output voltage, and other parameters are
programmable through the I2C interface.
The battery is charged using 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 included that monitors battery temperature and automatically
changes charge parameters to prevent the battery from charging outside of its safe temperature
range. The charger is optimized for 5-V USB input, with 20-V 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 4.65 V.
A configurable load switch allows system optimization by disconnecting infrequently used
devices. The manual reset with timer allows mutliple different configuration options for wake are
reset optimization. A simple voltage based monitor provides battery level information to the host
in 2% increments from 60% to 100% of the programmed V(BATREG).