| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage converting circuit in which high withstand voltage is not required for a switching means being arranged on the primary of a transformer. SOLUTION: A transformer T1 has a primary coil P1 and secondary coils S11, S12 whereas a transformer T2 has a primary coil P21 connected in series with the coil P1, a coil P22 and a secondary coil S21. A transistor Q1 turns DC voltage supply to the coil P1 on/off. When the transistor Q1 is turned on and a voltage is supplied to the coil P1, a diode D1 short-circuits the opposite ends of the coil P22. When the transistor Q1 is turned off and voltage supply is interrupted, a diode D2 short-circuits the series circuit of the coils P1 and P21. A DC voltage is outputted based on an electromotive force being induced in the coil S11 under a state where voltage supply is turned on by the transistor Q1, and a DC voltage is outputted based on an electromotive force being induced in the coils S12, S21 under a state where voltage supply is turned off. COPYRIGHT: (C)2007,JPO&INPIT
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