| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain a voltage conversion circuit capable of size reduction of a device and improvement in the conversion efficiency by omitting a transformer. <P>SOLUTION: The voltage conversion circuit includes: a rectifying circuit 2 for rectifying AC first voltage and outputting DC second voltage; a voltage step-down circuit 3 for stepping-down a second voltage and outputting a DC third voltage; and a voltage step-down circuit 4 for stepping-down the third voltage and outputting a fourth DC voltage. The voltage step-down circuit 3 has capacitors C1-C3, and transistors Q1-Q4 for switching the connection of the capacitors C1-C3 to serial connection in charging operations of the capacitors C1-C3 by the second voltage and to parallel connection in discharging operations of the capacitors C1-C3. The voltage step-down circuit 4 has a transistor Q5, and a capacitor C4 to be charged by the third voltage, when the transistor Q5 is in an energized state and discharged when the transistor Q5 is in a non-energized state. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
