Emergency power off (EPO) island for saving critical data to non-volatile memory

A method for instantiating a power island to save critical data in an emergency power off (EPO) situation in a hard disk drive (HDD) device, the method comprising:

• detecting an EPO condition affecting said HDD device;
• supplying power only to said power island of a hard drive controller and not to the rest of said hard drive controller;
• operating a reference clock for said power island, wherein said reference clock operates at a lower frequency than a frequency at which a system clock of said hard drive controller operates;
• and
• transferring data from volatile memory internal to said power island to non-volatile memory external to said power island.

A hard-drive controller electronic component comprising an emergency power off (EPO) power island, said EPO power island comprising:

• an EPO power island controller configured for detecting an EPO condition;
• a non-volatile memory interface configured for transferring data from memory internal to said EPO island to non-volatile memory external to said hard-drive controller;
• an oscillator configured for operating as a reference clock for said EPO power island, wherein said oscillator operates at a lower frequency than a frequency at which a system clock of said hard-drive controller operates;
• wherein only said EPO power island of said hard-drive controller and said non-volatile memory receive power from a voltage regulator in order to isolate said EPO power island and said non-volatile memory in response to said EPO condition;
• and
• wherein said power supplied from said voltage regulator is from a motor driver configured for using back electromotive force from a spindle motor of said hard-drive.