SLUSDF9 June 2020 BQ25790
The device monitors its internal junction temperature (TJ) to avoid overheating and to limit the IC surface temperature. When the internal junction temperature exceeds the preset thermal regulation limit (TREG bits), the device reduces the charge current or OTG output current to maintain the junction temperature at the thermal regulation limit. A wide thermal regulation range from 60°C to 120°C allows optimization of the system thermal performance. During thermal regulation, the actual charging current is usually below the programmed value in the ICHG registers. Therefore, termination is disabled, the fast charging safety timer runs at half the clock rate, the status register TREG_STAT bit goes high, TREG_FLAG bit is set to 1, and an INT is asserted to alert host unless TREG_MASK is set to 1.
Additionally, the device has thermal shutdown to turn off the converter when the IC junction temperature exceeds the TSHUT threshold. The fault register bits TSHUT_STAT and TSHUT_FLAG are set and an INT pulse is asserted to the host, unless TSHUT_MASK is set to 1. The BATFET and the converter resumes normal operation when the IC die temperature decreases lower than TSHUT threshold by TSHUT_HYS.