Method of operating storage device for retention enhancement and storage device performing the same

A storage device comprising:

• a storage controller;
• and
• a nonvolatile memory controlled by the storage controller, and
• wherein:
• the storage device is powered on based on an activation of an external power supply voltage,
• the storage controller is configured to wait for establishment of communication with a host device based on a link signal between the storage device and the host device, and
• without the establishment of communication with the host device, the storage controller is configured to perform a retention enhancement operation by entering a retention enhancement mode and by providing at least one command to the nonvolatile memory.

A method of operating a storage device including a storage controller and a nonvolatile memory, the method comprising:

• powering on the storage device based on an activation of an external power supply voltage;
• waiting for an establishment of communication with a host device based on a link signal between the storage device and the host device;
• in response to the establishment of communication with the host device being successfully completed, entering a normal operation mode;
• performing a normal operation in the normal operation mode;
• measuring an establishment of communication waiting time starting from a time point at which the external power supply voltage is activated;
• in response to the establishment of communication waiting time becoming longer than a first reference time, entering a retention enhancement mode without the establishment of communication with the host device;
• performing a retention enhancement operation in the retention enhancement mode by providing a read command and a reprogram command from the storage controller to the nonvolatile memory;
• and
• in response to the communication establishment of communication with the host device being successfully completed in the retention enhancement mode, exiting the retention enhancement mode and entering the normal operation mode, and
• wherein a criterion for determining whether data is degraded in the retention enhancement mode is higher than a criterion for determining whether data is degraded in the normal operation mode.