Patent ID: 8625313

Claim:
A control circuit for a switching power converter, the control circuit is installed between a secondary side of the switching power converter and an output of the switching power converter and coupled to control a switching device wherein the control circuit comprises: a linear predict circuit, coupled to receive a linear predict signal from the secondary side for generating a charging signal; a reset circuit, coupled to receive a resetting signal for generating a discharging signal; a charge/discharge circuit, coupled to receive the charging signal and the discharging signal for generating a ramp signal; and a pulse width modulation (PWM) circuit, coupled to receive the linear predict signal for enabling a switching signal and receive the ramp signal for resetting the switching signal: wherein the linear predict circuit comprises: a sample-and-hold circuit, coupled to receive the linear predict signal and generate a hold signal in response to the linear predict signal; and a voltage-to-current converter, coupled to receive the hold signal and generate the charging signal in response to the hold signal.