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. 11, 2006
Filed:
May. 12, 2004
Ta-yung Yang, Milpitas, CA (US);
Guo-kiang Hung, Sindian, TW;
Song-yi Lin, Taipei, TW;
System General Corp., Taipei Hsien, TW;
Abstract
A PWM controller having frequency jitter includes a modulator for generating a first jitter current and a second jitter current. An oscillator generates a pulse signal for producing a switching frequency in response to the modulation of the first jitter current. An attenuator is connected in a voltage feedback loop for attenuating a feedback signal to an attenuated feedback signal, in which the attenuated feedback signal is utilized to control an on-time of a switching signal. A variable-resistance circuit is connected with the attenuator for programming an attenuation rate of the attenuator in response to the modulation of the second jitter current. The switching frequency increases whenever the first jitter current increases. Meanwhile, the impedance of the attenuator will decreases and the attenuation rate will increase whenever the second jitter current increase. The on-time of the switching signal is thus immediately reduced, which compensates the decrease of the switching period and keeps the output power as a constant.