A method for phase compensating a power factor correction circuit is provided. Firstly, a present current value of an input current is sampled, and the sampled signal is filtered. Then, a present waveform of the input current corresponding to the present current value of the filtered sampled signal and a previous waveform of the input current corresponding to a previous current value of the filtered sampled signal are predicted, and a current error signal is generated according to a difference between the present waveform and the previous waveform. Then, the current error signal is adjusted, and an adjusted signal is generated. Then, a feedforward signal is added to the adjusted signal, and a phase compensation signal. Then, a current control signal is added to the phase compensation signal, and a pulse width modulation signal is generated to control a switching circuit.

A method for phase compensating a power factor correction circuit is provided. Firstly, a present current value of an input current is sampled, and the sampled signal is filtered. Then, a present waveform of the input current corresponding to the present current value of the filtered sampled signal and a previous waveform of the input current corresponding to a previous current value of the filtered sampled signal are predicted, and a current error signal is generated according to a difference between the present waveform and the previous waveform. Then, the current error signal is adjusted, and an adjusted signal is generated. Then, a feedforward signal is added to the adjusted signal, and a phase compensation signal. Then, a current control signal is added to the phase compensation signal, and a pulse width modulation signal is generated to control a switching circuit.