| 摘要 |
PROBLEM TO BE SOLVED: To solve various problems that a radio receiver incorporated electronic equipment such as a portable radio and a radio cassette recorder (a cassette recording tape incorporated radio) does not adopt a switching power supply circuit in which a noise occurs, but adopt a linear system of a silicon steel plate transformer, and in the linear system, it is difficult that the power consumption in the standby state is made equal to or lower than 1.5 W, and the conversion efficiency is poor and in the extent of 45%, when the voltage of an AC power supply fluctuates, a DC voltage of the load also fluctuates proportionally. SOLUTION: A higher harmonic noise of the switching power supply circuit is removed by operating in an approximate resonance voltage component which is a voltage of almost a sine wave, and a voltage not including a voltage component other than a DC voltage component. The power consumption in the standby state can be made equal to or lower than 0.3 W. Moreover, the conversion efficiency can be made equal to or more than 75%. Further, even if the AC power supply fluctuates by±10%, the voltage fluctuation of the load can be stabilized within±1%. COPYRIGHT: (C)2009,JPO&INPIT
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