| 摘要 |
PURPOSE:To provide a high voltage generating circuit which prevents switching loss by zero cross switching operation. CONSTITUTION:A transistor 13 is serially connected to one terminal side of a low voltage coil 12 of a flyback transformer 11, and a first damper diode 14 and a first resonance capacitor 15 are parallelly connected to the transistor 13. An MOS FET 17 and a driving power source 18 are serially connected to the other terminal side of the low voltage coil 12. A second damper diode 20 and a second resonance capacitor 21 are parallelly connected to the MOS FET 17. The ON/OFF switching operation of the MOS FET 17 is executed by a switch control circuit 16. The more drop amount of a high output voltage is made, the wider the pulse width of a driving pulse prepared by the switch control circuit 16 is obtained, and the driving pulse is impressed. When the transistor 13 is turned on, the MOS FET 17 is turned on at latest and while the transistor 13 is turned on, the MOS FET 17 is controlled to be turned off. |
