SLUSDC7A March 2020 – November 2020 BQ25306
The device monitors the junction temperature TJ to avoid overheating the chip and limit the device surface temperature. When the internal junction temperature exceeds thermal regulation limit TREG, the device lowers down the charge current. During thermal regulation, the average charging current is usually below the programmed battery charging current. Therefore, termination is disabled and the safety timer runs at half the clock rate.
Additionally, the device has thermal shutdown built in to turn off the charger when device junction temperature exceeds TSHUT rising threshold. The charger is reenabled when the junction temperature is below TSHUT falling threshold. During thermal shutdown, the safety timer stops counting and it resumes when the temperature drops below the threshold.