Patents by Inventor Cheng Yong Toeh

Cheng Yong Toeh 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 and method for detecting back electromotive force with automatic pole calibration
    Patent number: 7227321
    Abstract: A system and method for determining the rotational speed of a motor, such as a three-phase disk drive motor, detects back electromotive force voltage generated during operation of the motor with an automatic pole calibration to minimize or eliminating variations in the wave of a freeze signal. A phase voltage at a winding is compared against a center tap (CT) voltage. Once the phase voltage falls to a specified voltage level, a detect signal is generated. A predetermined time after the detect signal is generated, a freeze signal is generated for freezing at least the circuit associated with the winding.
    Type: Grant
    Filed: July 14, 2005
    Date of Patent: June 5, 2007
    Assignee: Marvell International Ltd.
    Inventors: Kuong Hoo, legal representative, Foo Leng Leong, Siew Yong Chui, Cheng Yong Toeh, Sakti Pada Rana, deceased