| 摘要 |
PURPOSE:To obtain the high voltage generating circuit with an excellent circuit efficiency in which a boosting ratio of a flyback transformer 11 is reduced to make the size of the flyback transformer 11 small and to reduce the cost and heat dissipation. CONSTITUTION:A primary coil 12 of a flyback transformer 11 and a transistor(TR) 13 are connected in series between a drive power supply 18 and ground. A diode 14 and a resonance capacitor 15 are connected in parallel with the TR 13. The series circuit comprising a dummy yoke 16 and a circuit block 10 is connected in parallel with the primary coil 12. The circuit block 10 is made up of a parallel circuit comprising a FET 17, a diode 20 and a capacitor 21. The MOS FET 17 is operated by a drive pulse whose on-pulse width is made narrow by quickening the off-time as a high output voltage drop increases. |
