Storage devices, storage systems and methods of operating storage devices

A storage device includes nonvolatile memory devices that store data, a storage controller, and an adaptive power supply circuit. The storage controller controls the nonvolatile memory devices. The adaptive power supply circuit generates at least one operation voltage based on at least one power supply voltage, and provides the at least one operation voltage to the nonvolatile memory devices and the storage controller. The at least one power supply voltage is provided to the adaptive power supply circuit through a portion of power lines connected to a host. Under control of the storage controller, the adaptive power supply circuit adaptively activates a power disable function associated with a provision of the at least one operation voltage according to a level of a third power supply voltage provided through a third power line of the plurality of power lines. The third power supply voltage is provided by the host.