Patent ID: 8351228

Claim:
A voltage conversion circuit connected between a power supply circuit and a load circuit, the voltage conversion circuit comprising: a plurality of capacitors; a switching circuit which switches the plurality of capacitors between serial connection and parallel connection to the power supply circuit and the load circuit, with a voltage input to the voltage conversion circuit from the power supply circuit being increased or decreased in accordance with the connection state of the plurality of capacitors; wherein the power supply circuit includes an AC power supply and a rectification circuit, which rectifies a voltage from the AC power supply; the switching circuit is connected to the AC power supply bypassing the rectification circuit and performs switching in accordance with a potential variation in the AC power supply; and a waveform shaping circuit which shapes a signal waveform of the potential variation into a rectangular signal waveform, wherein the switching circuit is connected to the power supply circuit via the waveform shaping circuit.