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:
May. 18, 2004
Filed:
Jul. 29, 2002
Prolific Technology Inc., Taipei, TW;
Abstract
A system for controlling the rotational speed of a fan, according to a reference clock having a reference frequency, is disclosed. The rotational speed corresponds to a fan rotational speed signal. The fan rotational speed controlling unit compares the reference clock with the fan rotational speed signal, to output a speed controlling signal. The Voltage generating circuit generates a level signal corresponding to the speed controlling signal. The driving unit generates a driving signal to control the rotational speed of the fan according to the level signal. When the fan is assembled with the controlling system, only coils with the same number of turns need to be use to obtain various rated rotational speeds of fans of different specifications by altering the reference frequency of the controlling system. Because coils with different number of turns are not required in stock at the same time, the time cost and the manufacturing cost can be reduced.