Single-stage pfc converter with constant voltage and constant current

A switching controller for a power converter comprising:

• a power device, coupled to switch a transformer of said power converter for regulating an output voltage and an output current of said power converter;
• an input circuit, coupled to said transformer to sample an input signal which is correlated to said output voltage of said power converter to obtain a feedback signal, wherein said feedback signal is utilized to generate a switching signal for controlling said power device, and said switching signal is modulated to operate said power converter in boundary current mode (BCM) or discontinuous current mode (DCM);
• and
• a compensation capacitor providing frequency compensation for a feedback loop of said power converter,
• wherein a bandwidth of said frequency compensation is lower than two times of a line frequency of said power converter to achieve approximately fixed on-time of said switching signal, and
• wherein an input capacitor connected to an input of said power converter is small enough to guarantee an input voltage having a full-wave rectified waveform to be received by said transformer.