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:
Sep. 09, 2003
Filed:
Aug. 10, 2001
Chia-Chang Hsu, Hsinchu, TW;
Chih-Shih Yang, Hsinchu, TW;
Prolific Technology Inc., Taipei, TW;
Abstract
A DC brushless motor operation speed control method is disclosed. First, a linearly voltage dependent current source is used to charge a capacitor and the terminal voltage of the capacitor is coupled to a linearly voltage dependent base frequency level detector. When the output voltage of the capacitor reaches the base frequency reference voltage, the signal output from the base frequency level detector will make the capacitor discharge, outputting a series of base frequency triangular waves. Under different supply voltages, all the generated base frequency triangular waves have the same cycle time. The base frequency triangular waves are transmitted to a speed control comparator. Through pulse width modulation, the speed control reference voltage adjusts the output pulse width of the comparator and thereby controls the speed of the motor.