Patents by Inventor Erno H. Klassen

Erno H. Klassen 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).

  • Disk drive with improved retract circuit and method
    Patent number: 6643087
    Abstract: A method and apparatus to provide a retract circuit that can correspond to the tendency toward miniaturization and low supply voltage. When drive supply voltage Vcc is applied, a retract circuit charges a retract condenser Cr with boosted voltage Vup, equal to three times Vcc, generated by a booster circuit. Then, if the drive supply voltage Vcc is cut off and a VCM driver stops, the retract circuit detects power-off with a power OFF sense circuit, and provides retract delay time by a retract delay circuit. Furthermore, when the retract delay time elapses after the drive power supply is turned off, the retract driver switches the switching circuits on, discharges the retract condenser, charged at the boosted voltage, supplies discharge current to a voice coil, and retracts the head assembly.
    Type: Grant
    Filed: March 6, 2000
    Date of Patent: November 4, 2003
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kenji Kuroki, Thomas R. Albrecht, Fuminori Sai, Yuzo Nakagawa, Nobuhisa Koide, Masashi Murai, Keishi Takahashi, Timothy C. Reiley, Erno H. Klassen