Patents by Inventor Chee Wai Lum

Chee Wai Lum has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • System, method, and device for a regenerative constant velocity park for voice coil motor
    Patent number: 6188540
    Abstract: A system, method, and device for moving a plurality of heads in a disk drive is disclosed. The system comprises hard disks, read/write heads for reading from or writing to the hard disks, a voice coil motor for moving the plurality of heads, a voice coil motor driver for energizing the voice coil motor, a voltage clamp device for regulating a voltage across the voice coil motor, and a park voltage source. The voltage clamp device comprises a transistor, a switch, and a resistive divider network. During head parking, a park voltage source activates the voltage clamp device, which clamps the voltage across the voice coil motor to a fixed value, resulting in movement of the voice coil and heads towards a park location with fixed velocity.
    Type: Grant
    Filed: June 30, 1998
    Date of Patent: February 13, 2001
    Assignee: Seagate Technology LLC
    Inventors: Kah Liang Gan, Beng Wee Quak, Kok Hoe Chia, Chee Wai Lum