| 摘要 |
PURPOSE: To provide a discharge-lamp lighting apparatus in which a circuit is constituted simply and by which an inverter circuit can be started surely. CONSTITUTION: After a DC power supply 1 has been turned on, the DC component of the DC power supply 1 is blocked by a capacitor C5, the noninverting input terminal of an operational amplifier OP1 keeps a low state by a reference power supply E2 at an inverting input terminal, and the operational amplifier OP1 outputs a noninverted signal. When 200μs elapses after the DC power supply has been turned on, a timer circuit 8 outputs a pulse signal, an H-level is input to the input terminal A of an OR circuit 1, the output terminal C of the OR circuit OR1 outputs an H-level signal, and a field-effect transistor Q1 is turned on. A drain current flows, the voltage of a resistor R1 is raised, an operational amplifier OP2 outputs a noninverted signal, and the field-effect transistor Q1 is turned off. The field-effect transistor Q1 repeats an ON- operation and an OFF-operation, an inverter circuit 2 is oscillated, and a fluorescent lamp FL is turned on at a high frequency. |
