公开(公告)号：SG83772A1

公开(公告)日：2001-10-16

申请号：SG200000797

申请日：2000-02-14

Applicant: IBM

Inventor： KENJI KUROKI ,  THOMAS ROBERT ALBRECHT ,  FUMINORI SAI ,  YUZO NAKAGAWA ,  NOBUHISA KOIDE ,  MASASHI MURAI ,  KEISHI TAKAHASHI ,  TIMOTHY CLARK REILEY ,  ERNO H KLASSEN

IPC: G11B21/02 ,  G11B19/04 ,  G11B21/12 ,  H02P8/12 ,  G11B5/54

Abstract: A method and apparatus to provide a retract circuit that can correspond to the tendency toward miniaturization and low supply voltage. When drive supply voltage Vcc is applied, a retract circuit charges a retract condenser Cr with boosted voltage Vup, equal to three times Vcc, generated by a booster circuit. Then, if the drive supply voltage Vcc is cut off and a VCM driver stops, the retract circuit detects power-off with a power OFF sense circuit, and provides retract delay time by a retract delay circuit. Furthermore, when the retract delay time elapses after the drive power supply is turned off, the retract driver switches the switching circuits on, discharges the retract condenser, charged at the boosted voltage, supplies discharge current to a voice coil, and retracts the head assembly.