Disk drive power control circuit and method
First Claim
1. A disk drive apparatus for driving a magnetic disk to read and write information therein, said disk drive apparatus having an actuator assembly for positioning a read/write head on the surface of the magnetic disk, a spindle motor for rotation of the magnetic disk, and an electronic circuit for controlling the operation of the above elements, wherein said disk drive apparatus further comprising:
- a memory for storing a set of information regarding (1) access time versus actuator drive current for said actuator assembly, and (2) start-up current versus frictional resistance in said spindle motor, where said access time is defined as the time required for said actuator assembly to transfer said read/write head from one position to another on said magnetic disk, and said start-up current is defined as the current required for said spindle motor to overcome said frictional resistance and to start rotation in order to reach a predetermined rotation speed;
a memory for setting a user access time in said disk drive apparatus by a user of the disk drive apparatus;
a micro-controller for evaluating said user access time and selecting the lowest possible actuator drive current within the range defined in said information in said memory to satisfy said user access time, said micro-controller selecting the actuator drive current selected immediately prior to the present operation when said user access time is not provided, said micro-controller further selecting the lowest possible start-up current for said spindle motor corresponding to said frictional resistance in the current state of said spindle motor with reference to said information; and
a current limiter for limiting a current level for said disk drive apparatus based on said current level determined by said micro-controller.
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Accused Products
Abstract
A disk drive control circuit and method controls electric power consumption in a disk drive so that a computer system such as a laptop computer can conserve power and as a result can dramatically reduce the effective life of batteries employed as a power source of the computer system. The disk drive control circuit and method is effective in reducing a power consumption for very small form factor disk drives. A technique is provided to allow the user to adopt the performance versus power consumption to meet the system requirements. The control circuit and method effectively controls transient currents associated with initiation of mechanical operation such as an actuator for actuating a magnetic head and a spindle motor for rotating a magnetic disk at high speed with optimum starting time. The disk drive control circuit and method includes a micro-controller for controlling a total operational procedure for reducing an electric power consumption programmed by a vendor or instructed by a user in addition to an overall operation of the disk drive. The disk drive control circuit also includes a memory for storing a set of programs for the operation of the disk drive. The memory includes profiles (such as current versus access time table) for the current control. An actuator current control limits the flow of current to the actuator based on instructions from the micro-controller. A spindle motor current control limits the flow of current to the spindle motor based on instructions from the micro-controller.
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Citations
11 Claims
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1. A disk drive apparatus for driving a magnetic disk to read and write information therein, said disk drive apparatus having an actuator assembly for positioning a read/write head on the surface of the magnetic disk, a spindle motor for rotation of the magnetic disk, and an electronic circuit for controlling the operation of the above elements, wherein said disk drive apparatus further comprising:
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a memory for storing a set of information regarding (1) access time versus actuator drive current for said actuator assembly, and (2) start-up current versus frictional resistance in said spindle motor, where said access time is defined as the time required for said actuator assembly to transfer said read/write head from one position to another on said magnetic disk, and said start-up current is defined as the current required for said spindle motor to overcome said frictional resistance and to start rotation in order to reach a predetermined rotation speed; a memory for setting a user access time in said disk drive apparatus by a user of the disk drive apparatus; a micro-controller for evaluating said user access time and selecting the lowest possible actuator drive current within the range defined in said information in said memory to satisfy said user access time, said micro-controller selecting the actuator drive current selected immediately prior to the present operation when said user access time is not provided, said micro-controller further selecting the lowest possible start-up current for said spindle motor corresponding to said frictional resistance in the current state of said spindle motor with reference to said information; and a current limiter for limiting a current level for said disk drive apparatus based on said current level determined by said micro-controller. - View Dependent Claims (2, 3, 4, 5)
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6. A disk drive apparatus for driving a magnetic disk to read and write information therein, said disk drive apparatus having an actuator assembly for positioning a read/write head on the surface of the magnetic disk, a spindle motor for rotation of the magnetic disk, and an electronic circuit for controlling the operation of the above elements, wherein said disk drive apparatus further comprising:
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a memory for storing a set of information regarding start-up current versus frictional resistance in said spindle motor, where said start-up current is defined as a current required for said spindle motor to overcome said frictional resistance and to start rotation for reaching a predetermined rotation speed; a micro-controller for evaluating said frictional resistance in the current state of said spindle motor and selecting the lowest possible start-up current for said spindle motor to start rotation with reference to said information in said memory; and a current limiter for limiting a level of said start-up current for said spindle motor according to the instruction from said micro-controller. - View Dependent Claims (7, 8, 9, 10)
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11. A method for determining a drive current level for a disk drive apparatus for use in a host computer, wherein said disk drive apparatus having a magnetic disk for storing information, an actuator assembly for positioning a read/write head on the surface of the magnetic disk, a spindle motor for rotation of the magnetic disk, and an electronic circuit for controlling the operation of the above elements, said method comprises the following steps of:
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storing a set of information regarding (1) access time versus actuator drive current for said actuator assembly, and (2) start-up current versus frictional resistance for said spindle motor, providing a user access time for said actuator assembly by a user of said disk drive apparatus, determining current levels for either said actuator assembly and said spindle motor based on said set of information wherein said current level for said actuator assembly is selectively determined based on said user access time or said set of information, and said current level for said spindle motor is determined based on the present condition regarding the frictional resistance against rotation in said spindle motor with reference to said set of information, and limiting drive current applying to said actuator and said spindle motor based on said determined current level.
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Specification