This invention is used of CD-to-AC converters or similar device. The main content of the invention is as follows: A series circuit composed of a capacitor and a reverse connecting diode is in parallel to ends of chopper switching diode as a energy stored circuit. Together with energy feeding circuit and precharged copacitive energy stored circuit, the energy in transformer is absorbed or released when transformer is reversed. As a result, the waveform is improved, the tramsformer efficiency is raised and the more power output is obtained.