Disk drive device
AssigneeSanyo Electric Co., Ltd.
InventorAkira Tsukihashi
Life of this patent
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Abstract
A mode setting circuit (13) establishes a maximum speed enabling mode when an external power source connection detecting circuit (12) detects connection of an external power source and establishes a maximum speed restricting mode when the external power source connection detecting circuit (12) does not detect connection of an external power source. Data processing at the maximum disk rotation speed is enabled when the external power source is connected and, when no external power source is connected, the disk rotation speed is restricted to a speed corresponding to a data transfer rate at which power required for the data processing can be supplied from an interface (1).
Claims6
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 to be installed;
- 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 requestable by said host device is not restricted and a maximum speed restricting mode in which said maximum disk rotation speed is restricted,
- wherein said mode setting circuit establishes the maximum speed enabling mode when said external power source connection detecting circuit detects the connection of the external power source and establishes the maximum speed restricting mode when said external power source connection detecting circuit does not detect the connection of the external power source.
Dependencies are inferred from the claim text.