Nippon Electric Co., Ltd.

Kenzo Okutsu

Koji Ebato

Yoshito Kato

A commercial power supply is connected to a rectifier DB through a low-pass filter LPF. A smoothing capacitor Cs, a series circuit consisting of voltage-dividing capacitors C,and C,and a series circuit consisting of switching elements Q,and Q,are connected in parallel to the output of the rectifier DB. Diodes D,and D,are connected in reverse parallel to the switching elements Q,and Q,respectively. A drive circuit DR is connected to the switching elements Q,and Q,Between a connecting point that is between the voltage-dividing capacitors C,and C,and a connecting point that is between the switching elements Q,and Q,a load circuit R consisting of a parallel circuit is connected. The parallel circuit includes an inductor Lo, a fluorescent lamp LT, and a resonance capacitor C,By turning the switching elements Q,and Q,on and off, the inductor Lo is caused to perform a step-up inverter operation, whereby stable high-frequency voltage with a high voltage is generated across both ends of the inductor Lo. As a result, a neutral point inverter capable of generating high-frequency voltage that has a high voltage and less &ldquo;undulation&rdquo; can be provided.

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Kanagawa-ken, Japan

Kenzo Okutsu