| 摘要 |
PURPOSE:To stably light a discharge lamp with a low power capacity as a whole by discharging the charges of a capacitor charged by an auxiliary power source at a relatively long time constant, raising the lighting with a slow power capacity, and feeding only the stationary current via a main power source with a low power capacity. CONSTITUTION:When the open voltage Vo is applied to a discharge lamp 1 by a high-voltage starter 2, an auxiliary power current I1 starts to flow. When the auxiliary power voltage V1 is made lower than the no-load voltage Vo2 of a main power source, a main current I2 starts to flow. The current I2 is thereafter controlled by a control circuit 8 to become the preset stationary current I2. The no-load open voltage of a main power source 3 is Vo2, it needs only to maintain the stationary voltage VS and the stationary current IS during excitation, thus no wide operating range is required, and the operating point can be set to the center of the control range. The safety and controllability of the output can be improved. |
