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:
Aug. 25, 2009
Filed:
Mar. 05, 2007
Chien-lung Chang, Taipei, TW;
Chao Chen, Taipei, TW;
Kuo-chung Kao, Taipei, TW;
ASUSTeK Computer Inc., Taipei, TW;
Abstract
A fan system includes a fan, a hysteresis circuit including a temperature sensor, a first operational amplifier having a negative input end coupled to the temperature sensor, and a second operational amplifier having a negative input end coupled to an output end of the first operational amplifier and having a positive input end coupled to a power supply for outputting a first voltage when the temperature sensed by the temperature sensor is greater than a first temperature, and for outputting a second voltage when the temperature sensed by the temperature sensor is lower than a second temperature. The fan system further includes a fan switch coupled to the hysteresis circuit and the fan for controlling a rotational speed of the fan according to the first voltage or the second voltage outputted from the hysteresis circuit. The first temperature is greater than the second temperature.