Low total harmonic distortion and high power factor correction power converters

A power converter comprising:

• a transformer magnetically coupling a primary side and a secondary side of the power converter, the transformer including:
• a primary winding configured to be coupled to an output of a rectifier, and
• a secondary winding configured to be coupled to an output load of the power converter;
• a switch coupled between the primary winding and a primary side ground and configured to control current flow in the primary winding;
• a controller circuit including an output node coupled to the switch, the controller circuit configured for:
• receiving by the controller circuit, a first signal proportional to a voltage across the primary winding of the transformer when the switch is on;
• receiving by the controller circuit, a second signal proportional to an output voltage of the power converter;
• generating a modification factor proportional to a ratio of the first signal and the second signal;
• generating a first waveform configured for a critical conducting mode of operation of the power converter;
• modifying the first waveform based on the modification factor and generating a second waveform based on the modified first waveform;
• and
• providing the second waveform at the output node of the controller circuit.

A method comprising:

• receiving a first signal by a controller circuit;
• receiving a second signal by the controller circuit;
• generating a modification factor proportional to a ratio of the first signal over the second signal;
• generating a first waveform configured for a critical conducting mode of operation of a power converter;
• modifying the first waveform based on the modification factor and generating a second waveform based on the modified first waveform;
• and
• delivering the second waveform at an output of the controller circuit.

A method comprising:

• applying a rectified voltage to a primary winding of a transformer, the primary winding being coupled to a switch and regulated by the switch;
• driving an output load by a secondary winding of the transformer;
• receiving by the controller, a first signal proportional to a voltage across the primary winding of the transformer when the switch is on;
• receiving by the controller, a second signal proportional to an output voltage of the power converter;
• providing an output waveform by the controller, wherein the output waveform of the controller is configured for a critical conducting mode of operation of the power converter based on a function of a ratio of the first signal and the second signal;
• and
• controlling the power converter by applying the provided output waveform of the controller to the switch.