| 摘要 |
PURPOSE:To cause a discharge lamp to fade out to extinct state, and ensure the proper re-start of the discharge lamp after extinction via the application of simple constitution. CONSTITUTION:The source voltage of a DC power supply E is converted to high-frequency voltage via an inverter circuit 1, thereby lighting a discharge lamp La at a high frequency. Also, DC voltage is applied to the discharge lamp La, using electric charge in the capacitor C1 of a DC voltage superposing circuit 2 charged with output from the inverter circuit 1. Also, when the operation of the inverter circuit 1 is stopped, the electric charge of the capacitor C1 of the circuit 2 is gradually released, thereby causing the discharge lamp La to fade out and be turned off. Also, even after the discharge lamp La is turned off, preheating current is supplied to the filament thereof, using the electric charge stored in the capacitor C1, thereby ensuring the proper re-start of the discharge lamp La after extinction. |
