Patent ID: 7489529
Filing Date: 2009-02-10
Classification: H02M

Abstract:
1. A control circuit having frequency modulation, comprising: a switching circuit, coupled to a feedback circuit to generate a switching signal for regulating an output of a power converter; wherein said feedback circuit receives said output of said power converter for producing a feedback signal to control said switching signal; a first oscillator, generating a clock signal to said switching circuit to determine a switching frequency of said switching signal; a programmable capacitor, connected to said first oscillator for modulating a frequency of said clock signal; a second oscillator, generating an oscillation signal, wherein an encoding circuit generates digital signals in response to said oscillation signal; and a programmable resistor, coupled to said feedback circuit for attenuating said feedback signal; wherein said digital signals control said programmable capacitor for modulating said switching frequency of said switching signal; and said digital signals control said programmable resistor for programming an attenuation rate of said feedback signal.