Boost-buck power factor correction

A circuit responsive to an input power supply signal at an input supply voltage that varies largely sinusoidally with time at a fundamental supply frequency, the circuit comprising:

• rectifier circuitry for largely performing full-wave rectification on the input power supply signal to produce a full-wave rectified supply signal at a full-wave rectified voltage and a full-wave rectified current susceptible of having at least one overtone of the fundamental supply frequency;
• a regulator for regulating the full-wave rectified voltage to produce a regulated power supply voltage with reduced voltage ripple;
• and
• control circuitry for measuring the at least one overtone in the full-wave rectified current and for providing the regulator with a primary control signal that causes the at least one overtone to be largely removed from the full-wave rectified current such that the full-wave rectified current largely tracks the full-wave rectified voltage in time-varying waveform.