Patent ID: 8717091

Claim:
A control circuit for a power converter, comprising: a shared pin, for coupling with an output end of the power converter through a resistor; a driving circuit, for coupling with a switch of the power converter to configure a conduction status of the switch; a current source circuit, coupled with the shared pin, for providing a current through the shared pin to the resistor in a first period; a sampling circuit, coupled with the shared pin, for sampling a signal on the shared pin in a first interval and a second interval of the first period to respectively generate a first sampling value and a second sampling value; and a signal processing circuit, coupled with the sampling circuit and the shared pin, for comparing the first sampling value with the second sampling value; wherein when a difference between the first sampling value and the second sampling value is less than a predetermined value, the signal processing circuit receives an output signal on the output end through the shared pin in a second period and configures at least one of a conduction time and a conduction frequency of the switch through the driving circuit according to at least one of the output signal and a computation value calculated according to the output signal.