Other

Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Lighting Corporation

Osram-Melco Ltd.

Masatomi Asayama

Hiroyasu Kisaichi

Fumitake Oowada

The discharge lamp lighting apparatus has a step-up/step-down converter comprising a transformer , a first switching element serially connected to the transformer on a side of a commercial ac power source , and a first diode and a first capacitor connected to the transformer on the load side; zero-cross detection means for detecting the zero-cross of voltage of the commercial ac power source ; a supplemental power circuit comprising a second diode connected to the junction between the transformer and the first switching element , a second capacitor for charging electric power stored in the coil of the transformer on a side of the commercial ac power source via the second diode , and a second switching element , a third diode and an inductance through which the energy charged in the second capacitor is supplied to the discharge lamp ; and a control circuit that operates the second switching element in the supplemental power means based on the output from the voltage zero-cross detection means during a predetermined period of time around the zero-cross.

Discharge lamp lighting apparatus and lamp apparatus

To provide a high-pressure discharge lamp lighting apparatus which is adapted to be used in common for several kinds of AC voltages such as 100 V and 200 V, which is small in size, and which can secure good starting property with less circuit loss in use at any of the AC voltages, the apparatus is provided with a diode bridge for rectifying an AC voltage, an active filter for converting, with a high power factor, an AC voltage into a DC voltage, a current limiting circuit for controlling the current to be made to flow in the high-pressure discharge lamp, an inverter for converting a DC voltage into a low-frequency AC voltage, a high-voltage pulse circuit for generating a high-voltage pulse for starting the high-pressure discharge lamp, and a control circuit for controlling the active filter, the current limiting circuit, the inverter, a discharge-lamp voltage detecting circuit, a discharge-lamp current detecting circuit and the high-voltage pulse circuit.

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Yokohama, Japan

Masatomi Asayama