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:
Apr. 25, 2000
Filed:
May. 19, 1998
Jerry Collings, Santa Clara, CA (US);
Chuong Nguyen, San Jose, CA (US);
Joseph James Judkins, III, Cedar Park, TX (US);
Donald E Alfano, Round Rock, TX (US);
Ali Tasdighi, San Jose, CA (US);
Quoi V Huynh, San Jose, CA (US);
Sang T Ngo, Cupertino, CA (US);
Telcom Semiconductor, Inc., Mountain View, CA (US);
Abstract
An apparatus for sensing the rotation of a brushless DC fan includes the fan and a sense/driver circuit and a capacitance. The sense/driver circuit is coupled to the fan to receive a sense input signal including a fluctuating electrical effect caused by fan commutation events. The sense/driver circuit processes the sense input signal to generate a sense output signal indicative of fan operation. The sense/driver circuit includes an integrated circuit. The integrated circuit includes a sense input pin, a ground return pin, a driver circuit, an integrated filter portion, a filter pin and a level detecting circuit. The capacitance is coupled to the filter pin to provide a filter with the integrated filter portion. The driver circuit includes a control terminal, a first current handling terminal coupled to the sense input pin and a second current handling terminal coupled to provide a ground return pat. The integrated filter portion includes a filter input coupled to at least one of the first and second current handling terminals of the driver circuit, and a filter output for providing a filter output signal to the level detecting circuit. The level detecting circuit generates the sense output signal from the filter output signal. The filter derives the filter output signal indicative of the fan commutation events responsive to receiving a signal at the sense input pin.