| 摘要 |
PROBLEM TO BE SOLVED: To suppress charging energy for parasitic capacitance around a transformer for higher power converting efficiency by generating a main pulsating wave signal corresponding to a waveform whose sinewave signal has been subjected to full wave rectification in a switching amplifying part. SOLUTION: A switching amplifying part SWA generates main pulsating wave voltage corresponding to the full wave rectification waveform of a sinewave signal from supplied DC power, and reverses the polarity of main pulsating wave voltage for each cycle with a polarity reversing part PSW to generate sinewave voltage corresponding to a ringing signal. A control circuit part CONT generates a reference pulsating wave signal VX1 corresponding to the full wave rectification of the sinewave signal, and a reference wave pulsating generation/polarity control part SSCC on/off-controls switches SW1 to SW4. A pulse duration converting part PSCC outputs a pulse signal VDR subjected to pulse duration modulation so as to increase a pulse duration in proportional to the level of the reference pulsating wave signal VX1. It is thus possible to suppress charging energy for higher power converting efficiency. |
