Power Management Integrated Circuits (PMICs)/ Supervisors provide highly integrated power management solutions in system control, battery management, interface, audio and other specific applications. PMICs help to extend battery life and reduce wasteful power dissipation in various end applications.
PMICs are responsible for monitoring the supply voltage (or current) levels on microprocessor systems to ensure that they are not too high or too low. In general, most PMICs are able to reset with an active high, active low or active high/ active low signal.
The following is a typical example using the APX811/812 series from Diodes to work with an MCU.
When the PMIC senses the power rail (Vcc) dropping under a certain level, the monitor will issue a reset (RESET) signal, and then this signal transmits to the MCU which was powered by the same power rail, to avoid any data corruption or incorrect transmissions during the power low.
When the power supply voltage resumes to normal, the monitor also “cancels” the reset signal to initialize the MCU once. There are also some monitors that include manual reset feature, such as the MR pin of the above figure, which can be used to reset the MCU via an external reset switch.