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. 13, 2003
Filed:
Nov. 21, 2001
Alexander Noam Teutsch, Dallas, TX (US);
Zbigniew Jan Lata, Dallas, TX (US);
David John Baldwin, Allen, TX (US);
Ross E. Teggatz, McKinney, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
The present invention relates to a motor drive system which comprises a fan controller circuit operable to generate a PWM control signal for control of a motor speed. The fan controller circuit comprises a current detection circuit and a motor speed determination circuit. The system further comprises a fan driver circuit operable to drive a motor at a duty cycle based on the PWM control signal from the fan controller circuit. The fan driver circuit comprises a current sink circuit operable to draw current from the PWM control signal when the PWM control signal is high and when the motor reaches a predetermined position. In the addition, the current detection circuit is operable to detect the current draw on the PWM control signal and provide an indication signal to the fan speed determination circuit associated with such detection. Further, the motor speed determination circuit is operable to determine the speed of the motor based upon a timing associated with successive current draw detections. The present invention also relates to a method of determining a motor speed which comprises driving a motor at a duty cycle dictated by a PWM control signal and detecting a predetermined rotor position of the motor. The method further comprises generating a current pulse based on the rotor position, wherein the current pulse is convolved with the PWM control signal, detecting the current pulse, and determining the motor speed using successive detected current pulses.