Removable type magnetic recording/reproducing device

Abstract

In a motor drive for driving a motor having three-phase coils in both a high rotation speed mode making the motor at a high rotation speed and a low rotation speed mode making the motor at a low rotation speed which is extremely lower than the high rotation speed, the motor drive comprises a mode selection circuit for making a connection of the three-phase coils unipolar and bipolar connections on the high and the low rotation speed modes, respectively. A frequency generation pattern detects a rotation speed of the motor. On the basis of the rotation speed detected by the frequency generation pattern, a combination of a PLL circuit and a driving transistor drives the motor at the high and the low rotation speeds on the high and the low rotation speed modes, respectively.

What is claimed is:  
     
         1 . A motor drive for driving a motor having three-phase coils in both a high rotation speed mode making said motor at a high rotation speed and a low rotation speed mode making said motor at a low rotation speed which is extremely lower than the high rotation speed, said motor drive comprising: 
 mode selection means for making a connection of the three-phase coils unipolar and bipolar connections on the high and the low rotation speed modes, respectively;    rotation speed detecting means for detecting a rotation speed of said motor; and    driving means, connected to said mode selection means and said rotation speed detecting means, for driving, on the basis of the rotation speed detected by said rotation speed detecting means, said motor at the high and the low rotation speeds on the high and the low rotation speed modes, respectively.    
     
     
         2 . A motor drive as claimed in    claim 1   , wherein said rotation speed detecting means comprises a frequency generation pattern formed on a stator of said motor.  
     
     
         3 . A motor drive as claimed in    claim 1   , wherein the high rotation speed is a rotation speed ten times or more as large as the low rotation speed.  
     
     
         4 . A motor drive as claimed in    claim 3   , wherein the high rotation speed has the number of revolution of 3,600 rpm, the low rotation speed has the number of revolution of 300 rpm.  
     
     
         5 . A motor drive as claimed in    claim 3   , wherein the high rotation speed has the number of revolution of 3,600 rpm, the low rotation speed has the number of revolution of 360 rpm.  
     
     
         6 . A motor drive as claimed in    claim 1   , wherein said motor is a spindle motor.  
     
     
         7 . In a high-density/low-density compatible type flexible disk drive for enabling to carry out data recording and reproducing operation to and from disk-shaped magnetic recording media of both a large-capacity and a small-capacity flexible disks, the magnetic recording medium of the large-capacity flexible disk requiring to rotate at a high rotation speed on recording and reproducing, the magnetic recording medium of the small-capacity flexible disk requiring to rotate at a low rotation speed which is extremely lower than the high rotation speed on recording and reproducing, said high-density/low-density compatible type flexible disk drive comprising a motor having three-phase coils for driving the magnetic disk media of both the large-capacity and the small-capacity flexible disks and a motor drive for driving said motor in both a high rotation speed mode making said motor at the high rotation speed and a low rotation speed mode making said motor at the low rotation speed, wherein said motor drive comprising: 
 mode selection means for making a connection of the three-phase coils unipolar and bipolar connections on the high and the low rotation speed modes, respectively;    rotation speed detecting means for detecting a rotation speed of said motor; and    driving means, connected to said mode selection means and said rotation speed detecting means, for driving, on the basis of the rotation speed detected by said rotation speed detecting means, said motor at the high and the low rotation speeds on the high and the low rotation speed modes, respectively.    
     
     
         8 . A high-density/low-density compatible type flexible disk drive claimed in    claim 7   , wherein said rotation speed detecting means comprises a frequency generation pattern formed on a stator of said motor.  
     
     
         9 . A high-density/low-density compatible type flexible disk drive as claimed in    claim 7   , wherein the high rotation speed is a rotation speed ten times or more as large as the low rotation speed.  
     
     
         10 . A high-density/low-density compatible type flexible disk drive as claimed in    claim 9   , wherein the high rotation speed has the number of revolution of 3,600 rpm, the low rotation speed has the number of revolution of 300 rpm.  
     
     
         11 . A high-density/low-density compatible type flexible disk drive as claimed in    claim 9   , wherein the high rotation speed has the number of revolution of 3,600 rpm, the low rotation speed has the number of revolution of 360 rpm.  
     
     
         12 . A high-density/low-density compatible type flexible disk drive as claimed in    claim 7   , wherein said motor is a spindle motor.  
     
     
         13 . A removable type magnetic recording/reproducing device for enabling to removably access a large-capacity flexible disk comprising a disk-shaped magnetic recording medium and a shell for receiving the disk-shaped magnetic recording medium, the shell having large-capacity identifier means for identifying the large-capacity flexible disk in distinction from a different-capacity flexible disk, said disk-shaped magnetic recording medium comprising a plurality of tracks thereon which are arranged with concentric circles around a center of rotation thereof, each track being divided in a circumferential direction into a predetermined number of sectors having a length equal to one another, said plurality of tracks being separated in a radial direction into a user data area which is available to a user and an alternate area other than the user data area, said alternate area having a specific sector for storing capacity information indicative of a storage capacity of said disk-shaped magnetic recording medium, wherein said removable type magnetic recording/reproducing device comprises: 
 large-capacity detecting means disposed at a position corresponding to said large-capacity identifier means; and    means, connected to said large-capacity detecting means, for recognizing the storage capacity of said disk-shaped magnetic recording medium by reading the capacity information out of the specific sector on said disk-shaped magnetic recording medium of the large-capacity flexible disk.