| 摘要 |
PURPOSE:To prevent a momentary flash and an abnormal mode by operating a reset means in a time when abnormality is not caused in an electric power interrupted main circuit and an electric discharge lamp or in a shorter time than at the time of control voltage drop for normal work. CONSTITUTION:A time constant is set so that an inclination of voltage V1 of capacitor C1 becomes gentler than a descent inclination of voltage V2 of capacitor C2 when AC electric power supply E is turned off. Thereby, output of operation amplifiers OP1 and OP2 outputs 'H', and a transistor Q1 is turned on by the 'H' of the OP1, and a C2 discharge electricity by a resistor R1 and a loop of the Q1, and the voltage V2 runs low rapidly. Oscillation of a control part 25 is rest by the 'H' of the OP2, and stops output of an inverter 22. As a result, a momentary flash after the electric power supply E is cut off or an abnormal mode of the inverter can be prevented. A time to operate a control means by a reset means is quickened more than a shorter time among a time Ta when abnormality is not caused in an electric discharge lamp or a time Tb when control voltage capable of operating the control means normally. |
