| 摘要 |
A dimming ballast for HID lamps automatically controls illuminance according to an external environment as a natrium lamp or a metal halide lamp by coupling a communication control unit with a ballast for HID lamps. A full-wave rectification and the filter unit(110) full-wave rectifies the AC voltage inputted from an EMI filter and converts the AC voltage into the DC voltage. An active power factor improving unit(120) is composed of an inductor, a diode, and an IC for the power factor improvement and a switching element. An output circuit unit is composed of a half bridge circuit consisting of the DC-link voltage which is the output of the power factor improving unit, and a driving IC driving two switch elements of the lamp connected to an LCC resonance circuit. A counter circuit unit(180) controls the initial igniting of the lamp and stops the operation of the driving IC if the fixed time is over. |
