| 摘要 |
PURPOSE:To prevent the abnormal operation at the time when the power is turned on by inhibiting an inverter from starting until a specified period of time is measured by a timer after a step-up chopper is started up in the equipment wherein the self-excited inverter circuit is connected to the output side of the step up chopper circuit. CONSTITUTION:When a commercial ac supply E is turned on, a capacitor C13 of a step-up chopper circuit 23 is charged and a transistor Q15 comes to an on-state. Therefore, even if a capacitor C14 is charged and then a trigger device Q14 gets turned on, the gate voltage is not applied to a field effect transistor Q13 of an inverter circuit 25 and thereby the inverter circuit 25 does not oscillate. After that, when the capacitor C13 is charged and the step-up chopper circuit 23 starts operation, voltage is induced in a coil L12. When capacitors C17, C18 are fully charged, a Zener diode ZD1 comes to a reverse-blocking state and voltage is applied to the gate of the Q13 and then the inverter circuit 25 oscillates and thereby a fluorescent lamp FL light. |
