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:
Jun. 24, 2008
Filed:
Feb. 27, 2007
Ta-yung Yang, Milpitas, CA (US);
Guo-kiang Hung, Sindian, TW;
Song-yi Lin, Taipei, TW;
System General Corp., Taipei Hsien, TW;
Abstract
A switching controller having frequency hopping is used for reducing the EMI of a power supply. A pattern generator generates a digital pattern code in response to a clock signal. An oscillator generates an oscillation signal for determining a switching frequency of a switching signal. A programmable capacitor coupled to the oscillator modulates the switching frequency in response to the variation of the digital pattern code. An attenuator connected to a voltage feedback loop attenuates a feedback signal. The feedback signal controls the pulse width of the switching signal. A programmable resistor coupled to the attenuator determines an attenuation rate of the attenuator in response to the digital pattern code. The attenuation rate is increased as the switching frequency increases. The pulse width of the switching signal is thus reduced, which compensates the decrease of the switching period and keeps the output power and the output voltage constant.