Disk drive device

• US 20020171980A1
• Filed: 05/17/2002
• Published: 11/21/2002
• Est. Priority Date: 05/18/2001
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Tsukihashi, Akira
• Granted Patent: US 7,000,134 B2
• Time in Patent Office: Days
• US Class Current: 360/220
• CPC Class Codes: G11B 19/28 Speed controlling, regulating, or indicating G11B19/24 takes precedence

Abstract

At the time of data recording onto a disk, when an external power source connection detecting circuit (12) detects that connection of an external power source is released, the currently set rotation speed is recognized. When the current rotation speed cannot be achieved in a maximum speed restricting mode, the processing speed is switched to the maximum speed that can be achieved in the maximum speed restricting mode. At the time of data reproduction on a disk, when the external power source connection detecting circuit (12) detects that the connecting power source is switched to the external power source, the processing speed is automatically switched to the maximum disk rotation speed regardless of the maximum speed restricting mode.

Claims

1. A disk drive device which is connected to a host device via an interface capable of supplying power and can be supplied with power from either said interface or an external power source, said disk drive device comprising:

a speed control circuit for controlling the rotation speed of a disk installed in said disk drive device;

an external power source connection detecting circuit for detecting connection of said external power source; and

a mode setting circuit for selectively establishing, in accordance with a detection output from the external power source connection detecting circuit, a maximum speed enabling mode in which the maximum disk rotation speed achieved by said host device is not restricted or a maximum speed restricting mode in which said maximum disk rotation speed is restricted,

wherein, during data recording onto the disk, said mode setting circuit sets the rotation speed of the disk at the rotation speed which can be achieved in the maximum speed restricting mode when said external power source connection detecting circuit is unable to detect that the external power source is connected.

2. A disk drive device according to claim 1, wherein

during data recording onto the disk, said mode setting circuit determines the current rotation speed of the disk when said external power source connection detecting circuit detects that the external power source has been disconnected, and maintains the current rotation speed when the current rotation speed is one that can be achieved in the maximum speed restricting mode.

3. A disk drive device according to claim 1, further comprising a buffer memory for temporarily storing data transferred from the host device,

wherein when, during data recording onto the disk, the possibility of buffer underrun in said buffer memory is detected because the speed of transfer of data from the host device is less than the speed of reading of data from said buffer memory, said mode setting circuit switches the rotation speed of the disk from its present speed to a rotation speed which can be achieved in the maximum speed restricting mode,.

6. A disk drive device according to claim 1, wherein said interface is a USB (Universal Serial Bus) interface, provides a lower version compatibility enabling a lower communication speed and an upper version compatibility enabling a higher communication speed, and reports to said host device that the interface can adopt the upper version when said external power source connection detecting circuit detects the connection of the external power source and that the interface can adopt the lower version when said external power source connection detecting circuit does not detect the connection of the external power source.

4. A disk drive device which is connected to a host device via an interface capable of supplying power and which can be supplied with power from either said interface or an external power source, said disk drive device comprising:

a speed control circuit for controlling the rotation speed of a disk installed in said disk drive device;

an external power source connection detecting circuit for detecting connection of said external power source; and

a mode setting circuit for selectively establishing, in accordance with a detection output from the external power source connection detecting circuit, a maximum speed enabling mode in which the maximum disk rotation speed achieved by said host device is not restricted or a maximum speed restricting mode in which said maximum disk rotation speed is restricted,

wherein, during data reproduction on the disk, said mode setting circuit sets the rotation speed of the disk at the maximum speed when said external power source connection detecting circuit detects that the connecting power source is switched to the external power source.

5. A disk drive device according to claim 4, wherein an automatic speed setting condition in which the rotation speed of the disk can be set regardless of a mode set by said mode setting circuit can be established, and, under this automatic speed setting condition, the rotation speed of the disk is automatically switched to the maximum speed when said external power source connection detecting circuit detects that the connecting power source is switched to the external power source.