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. 07, 2002
Filed:
Feb. 14, 2001
Alex Horng, Kaohsiung, TW;
Nan Long Tsai, Kaohsiung, TW;
Sunonwealth Electric Machine Industry Co., Ltd., Kaohsiung, TW;
Abstract
A fan motor whose speed is controlled by an operating period of pulse waves includes first and second rectifying circuits, a voltage comparison circuit, and a differential amplifier. A pulse wave is inputted into the first rectifying circuit, an actual speed signal detected from the fan is inputted into the second rectifying circuit, and the pulse wave and the speed signal are compared in the voltage comparison circuit. After comparison, a comparison voltage is outputted to a negative terminal of the differential amplifier. A partial voltage from a source voltage is connected to a positive terminal of the differential amplifier. The differential amplifier outputs a drive voltage after calculating a voltage difference between the comparison voltage and the partial voltage. Speed of the fan is changed in response to a change in the value of the drive voltage.