| 摘要 |
PURPOSE:To invariably control a discharge lamp at the constant light quantity rising characteristic regardless of the production dispersion of the discharge lamp and allow instant lighting by controlling the discharging current to match with the reference characteristic value. CONSTITUTION:Whether the difference between the value I of the discharging current VR and the preset reference characteristic value Itn is the preset value A or below is judged. When the discharging current is larger than the reference value and the terminal voltage is smaller than the reference value, the current value must be reduced, thus the frequency Fc of the signal S1 controlling a converter circuit 2 is set to a value lower than before. The output voltage of the converter circuit 2 is reduced when the frequency Fc is decreased, and the discharging current can be decreased. When the temperature rise curve in a bulb is controlled by adjusting the discharging current, the light quantity can be controlled. |
