| 摘要 |
A power converter is provided which comprises two main MOS-FETs 4, 5 connected in series to a DC power source 1; an oscillator 2 which has two capacitors 3a, 3b connected in parallel to main MOS-FETs 4, 5; a primary winding 9a of a transformer 9 connected between a junction of two main MOS-FETs 4, 5 and a junction of two capacitors 3a, 3b; an electricity controller 12, 37 which comprises first and second regulatory MOS-FETs 10, 35, 12, 37 connected between respectively one and the other ends of a secondary winding 9b, 9c of transformer 9 and a speaker 15, 40; a polarity detector 51 for detecting the polarity of AC voltage produced on secondary winding 9b, 9c of transformer 9 by the on and off operation of MOS-FETs 4, 5 to generate detection signals; and a drive circuit 24, 25, 49, 50 for receiving detection signals from polarity detector 51 to control the on and off operation of first and second regulatory MOS-FETs 10, 35, 11, 36 to simplify the circuit configuration and improve power conversion efficiency in the power converter.
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