Patent ID: 8040074
Filing Date: 2011-10-18
Classification: H05B,Y02B

Abstract:
1. A discharge-lamp lighting device, comprising: a DC/DC converter that converts a power supply voltage of a DC power supply and stably lights a high-intensity discharge lamp; a DC/AC inverter that converts the DC voltage into an AC voltage; and a starting circuit that has a resonance circuit composed of at least one or more capacitors and inductors, and supplies an output from the DC/AC inverter to the high-intensity discharge lamp, wherein upon start-up of the high-intensity discharge lamp, a period during which the starting circuit applies a high voltage generated by resonance operation of the resonance circuit to the high-intensity discharge lamp when the DC/AC inverter outputs a high-frequency voltage, and a period during which the DC/AC inverter applies a low-frequency-square-wave voltage or a DC voltage to the high-intensity discharge lamp via the starting circuit, are output in an alternate manner, while the high-intensity discharge lamp is lighted, the DC/AC inverter applies the low-frequency -square-wave voltage to the high-intensity discharge lamp via the starting circuit, and the period for applying the high-voltage by the resonance operation is set to about a time enough for a high-intensity discharge lamp in an initial stage of a service life thereof to cause a dielectric breakdown, and a period for outputting the high-voltage generating period and the low-frequency-square-wave voltage or DC voltage generating period in the alternate manner is set to about a time enough for a high-intensity discharge lamp in a last stage of the service life thereof to cause the dielectric breakdown.