Patent ID: 6963176
Filing Date: 2005-11-08
Classification: H05B,Y02B,Y10S

Abstract:
1. A discharge lamp operation apparatus, comprising: an AC power supply; a rectifying circuit that rectifies a voltage from the AC power supply; a voltage converting circuit that has at least one switching element and converts the output voltage from the rectifying circuit to a specified voltage; an inverter circuit that has at least one switching element and converts the output voltage of the voltage converting circuit to a high-frequency voltage; a load circuit that includes a discharge lamp and LC resonant circuit and is connected to the inverter circuit; a controller that drives the switching element included in the voltage converting circuit; and a driver that drives the switching element included in the inverter circuit at a specified driving frequency, wherein the controller varies the output voltage of the voltage converting circuit to carry out dimming control of the discharge lamp, and the operation apparatus further comprises a pulse voltage superimposing section that superimposes a pulse voltage to the voltage applied across the discharge lamp under the condition where the dimming control is carried out in the vicinity of a lower limit of a dimming ratio.