The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 05, 2007
Filed:
Jul. 14, 2005
Kuong Hoo, Legal Representative, Singapore, SG;
Foo Leng Leong, Singapore, SG;
Siew Yong Chui, Singapore, SG;
Cheng Yong Toeh, Singapore, SG;
Kuong Hoo, legal representative, Singapore, SG;
Foo Leng Leong, Singapore, SG;
Siew Yong Chui, Singapore, SG;
Cheng Yong Toeh, Singapore, SG;
Marvell International Ltd., Hamilton, BM;
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.