System for controlling rotational speed of fan according to reference clock frequency
US6737860B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 2002 |
| Grant date | May 18, 2004 |
| Priority date | — |
| Expiry date | Jul 29, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K7/20209
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.