公开(公告)号：JPH1155989A

公开(公告)日：1999-02-26

申请号：JP16715398

申请日：1998-06-15

Applicant: ST MICROELECTRON INC

Inventor： BRAMBILLA MASSIMILIANO ,  NGUYEN CHINH DAC ,  LEE EUGENE C

IPC: G11B19/22 ,  H02P6/24

Abstract: PROBLEM TO BE SOLVED: To completely brake a spindle motor, by generating a brake signal when a power supply signal represents that a voltage supply source is insufficient and a voltage at a filter capacitor is a threshold value or less, and braking the motor. SOLUTION: When a voltage supply source VSUPP is completed, a rotor continues rotating for inertial mass and generates a counter-EMF voltage. This counter-EMF voltage is applied to a filter capacitor 58, and the voltage across the capacitor 58 is maintained. A voltage across the capacitor 58 is dropped as the rotor is decelerated due to a frictional effect. And, if the voltage is lowered to a input threshold value or less, a timing circuit 100 supplies a logic '1' to its output terminal and starts braking. Thus, a delay occurs between the end of the voltage VSUPP and braking of a spindle motor 32. Hence, since the motor 32 is dynamically braked after the rotor is decelerated, it can be safely braked.