Patent ID: 6975479
Filing Date: 2005-12-13
Classification: G11B

Abstract:
1. A magnetic disc storage apparatus comprising: a magnetic head for reading information from storage tracks on a magnetic disc driven to rotate; a voice coil motor for moving said magnetic head over said magnetic disc; and a magnetic head driving circuit for controlling positioning of said magnetic head and for executing a first drive mode and a second drive mode by feedback control in connection with a drive current of said voice coil motor while monitoring a read condition of said magnetic head, wherein said magnetic head driving circuit drives both terminals of a coil of said voice coil motor with linear control in said first drive mode, and drives one terminal of said coil with linear control and the other terminal of said coil with pulse width control in said second drive mode, wherein said magnetic head driving circuit executes said first drive mode during a tracking operation in which said magnetic head sequentially scans a plurality of adjacent storage tracks on said magnetic disc and also executes said second drive mode during a first seek operation in which an amount of movement of maid magnetic head is larger than an amount of movement of said magnetic head during a second seek operation.