Patent ID: 6949885

Claim:
A discharge lamp lighting device comprising: a rectifier for rectifying an AC power source; a DC power source circuit including at least one smoothing capacitor and connected to an output terminal of the rectifier; an inverter circuit, which includes two switching elements coupled in series to each other and is connected to an output terminal of the DC power source circuit, for turning the switching elements on and off alternately; a load circuit, which includes at least one resonance inductor, one resonance capacitor and one discharge lamp, for lighting the discharge lamp by a resonance generated by using a high frequency voltage inputted from the inverter circuit; a control IC for controlling operations of the switching elements of the inverter circuit; and a control power source circuit for supplying a control power to the control IC, wherein the control IC includes: a first timer unit for determining a status conversion timing for performing a shift from a preheating status, where the discharge lamp is preheated, to an ignition status, where an ignition voltage is applied to the discharge lamp, and finally to a lighting status, where the discharge lamp is lighted with a predetermined output power; a first control unit for determining an on/off timing of the switching elements of the inverter circuit based on a control signal provided from the first timer unit and outputting a driving signal to the switching elements of the inverter circuit; a second control unit for controlling variations in the cycle of the driving signal and generation of the driving signal provided from the first control unit based on a control signal inputted from an exterior of the control IC to perform a dimming control of the discharge lamp or a control of the inverter circuit; an operation status output unit for outputting a predetermined status signal corresponding to an operational status of the IC control circuit; and an operation setting circuit for inputting the status signal provided from the operation status output unit and outputting a control signal to the second control unit, wherein the operation status output unit outputs a status signal corresponding to at least the lighting status.