| 摘要 |
PURPOSE:To avoid wastefully reducing charge energy by generating fixed voltage across a gate and emitter of the first switching element by a constant voltage element, and turning off the gate of the first switching element by the second switching element. CONSTITUTION:When a switch 2 is turned on, a power supply battery 1 is connected to a boost circuit 3, to start a constant voltage circuit 15. Then, fixed voltage Vcc is generated in the circuit 15, and the fixed voltage is supplied to a microcomputer 17, to generate fixed voltage across a gate and emitter of a switching element of a switch circuit 16. Here from the microcomputer 17, when an oscillation start signal OSC is output from low to high, an NPN transistor Tr32 is turned on through a diode 35. Simultaneously with the above, a PNPTr31 is also turned on, and the power supply 1 is supplied to an oscillating transformer 36a to start oscillation. Thus by generating high voltage in an oscillating transformer 36C, the charging of a main capacitor 6 is started through diodes 4, 29. When a level of charge voltage is made capable of emitting a flash discharge tube 14, the OSC signal is output low to stop oscillation. |
