The TPS3600 family of supervisory circuits monitor and control processor activity. In case of power-fail or brownout conditions, the backup-battery switchover function of TPS3600 allows to run a low-power processor and its peripherals from the installed backup battery without asserting a reset beforehand.

During power on, RESET is asserted when the supply voltage (V_DD or V_BAT) becomes higher than V_res. Thereafter, the supply voltage supervisor monitors V_OUT and keeps RESET output active as long as V_OUT remains below the threshold voltage (V_IT). An internal timer delays the return of the output to the inactive state (high) to ensure proper system reset. This delay timer starts its time-out, after V_OUT has risen above the threshold voltage (V_IT).