Patent ID: 8928300
Filing Date: 2015-01-06
Classification: H02M

Abstract:
1. A control circuit of a switching power converter, wherein the switching power converter comprises a power switch, and is configured to convert an input voltage into an output voltage, the control circuit comprises: a first time generating circuit configured to generate a first time signal, wherein the OFF-time of the power switch is controlled by the first time signal; a phase lock circuit configured to generate a second time signal, wherein the ON-time of the power switch is controlled by the second time signal; and a switching signal generating circuit coupled to the first time generating circuit and the phase lock circuit, wherein based on the first time signal and the second time signal, the switching signal generating circuit generates a switching signal to control the ON and OFF switching of the power switch; wherein the phase lock circuit comprises an error generating circuit, the error generating circuit having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal is configured to receive the reference clock signal, and wherein the second input terminal is coupled to the switching signal generating circuit to receive the switching signal, and wherein based on the frequency difference between the reference clock signal and the switching signal, the error generating circuit generates an error signal at the output terminal, and wherein the phase lock circuit adjusts the second time signal in accordance with the error signal, and wherein the phase lock circuit generates the second time signal in accordance with the frequency difference between the switching signal and a reference clock signal, so as to get the frequency of the switching signal to be substantially equal to the frequency of the reference clock signal.