By Texas Instruments 23
Texas Instruments' BQ25150 is a highly integrated battery charge management IC that integrates the common functions for wearable devices including a charger, an output voltage rail, an ADC for battery and system monitoring, and a push-button controller.
The BQ25150 IC integrates a linear charger that enables quick and accurate charging for small batteries. The device supports charge current up to 500 mA and termination current down to 0.5 mA for maximum charge. The battery is charged using a standard Li-Ion charge profile with three phases including pre-charge, constant current, and constant voltage regulation.
The device integrates advanced power-path management and control that allowing the device to provide power to the system while charging the battery even with poor adapters. The host can control the power-path through I2C allowing it to disconnect the input adapter and/or battery without physically removing them. The single push-button input eliminates the need for a separate button controller IC, reducing the total solution footprint. The push-button input can be used for wake functions or to reset the system. A 12-bit effective ADC enables accurate battery voltage monitoring and can be used to enable a low IQ gauging to monitor battery health. It can also be used to measure the battery temperature using a thermistor connected to the TS pin and external system signals through a pin. The low quiescent current during operation and shutdown enables maximum battery life. The input current limit, charge current, LDO output voltage, and other parameters are programmable through the I2C interface making the BQ25150 a very flexible charging solution. A voltage-based JEITA compatible (or standard HOT/COLD) 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 temperature thresholds are programmable through I2C allowing the host to customize the thermal charging profile. The charger is optimized for 5 V USB input with 20 V absolute maximum tolerance to withstand line transients. The device integrates a linear regulator to provide a quiet rail for radios or processors and can be independently sourced and controlled through I2C.