Disk drive with improved retract circuit and method

A disk drive comprising:

• a disk recording medium;
• a head assembly having a magnetoresistive head capable of reading data from and writing data to said disk recording medium;
• a voice coil motor for swiveling said head assembly;
• and
• a retract circuit for retracting said head by driving said voice coil motor when a power supply for said disk drive is turned off, wherein said retract circuit includes
• a booster circuit capable of boosting a power supply voltage when said power supply is turned on;
• a condenser connected to said booster circuit;
• and
• a control circuit for allowing said condenser to be charged by said booster circuit with a boosted supply voltage when said power supply is turned on, and for allowing said condenser to discharge a discharge current to a coil within a head actuator of said disk drive, when said power supply is turned off, to retract a head assembly of said disk drive such that said head assembly is retracted even after said power supply has been turned off.

A method for retracting a head assembly of a disk drive, said method comprising:

• providing a booster circuit, a condenser, and a control circuit to a disk drive;
• charging said condenser via a boosted supply voltage provided by said booster circuit when a power supply for said disk drive is turned on;
• and
• in response to said power supply for said disk drive being turned off, discharging said condenser by said control circuit to supply a discharge current to a coil within a head actuator of said disk drive to retract a head assembly of said disk drive such that said head assembly is retracted even after said power supply has been turned off.