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:
Oct. 14, 2008
Filed:
Mar. 29, 2005
Hong-chun LI, Gaushu Township, Pingtung County, TW;
Chean-lung Tsay, Hsinchu, TW;
Dan Chen, Taipei, TW;
Hong-Chun Li, Gaushu Township, Pingtung County, TW;
Chean-Lung Tsay, Hsinchu, TW;
Dan Chen, Taipei, TW;
Richtek Technology Corp., Hsinchu, TW;
Abstract
In a power factor corrector including a PWM switch to switch a line current generated from a line voltage to charge a boost capacitor to thereby generate an output voltage, a piecewise on-time modulation apparatus and method comprise comparing a line voltage dependent voltage with an output voltage dependent voltage to generate a comparison signal to determine the on-time of the PWM switch. When the line voltage is lower than a threshold, the on-time of the PWM switch varies with the line voltage, and when the line voltage is higher than the threshold, the on-time of the PWM switch is constant.