A power management integrated circuit (PMIC) capable of operating, in memory systems, as a master control in power management in some situations and operating as a slave control in power management in other situations. For example, when used in a memory system operating on a SATA bus, the PMIC assumes the master control by monitoring the bus signals for entering or existing a sleep mode or a power shutdown mode, communicating to the controller of the memory system to prepare for the respective mode, and when ready, adjusting power states for the mode changes. For example, when used in a memory system operating on a PCIe bus, the PMIC assumes the slave control during a normal mode and a sleep mode, but the master control when the memory system is in a power disable mode in which the controller of the memory system is powered off.