Patent ID: 7973497

Claim:
A discharge tube lighting apparatus comprising: a converter arranged to convert a power supply voltage received from an alternating-current power supply or a direct-current power supply into a direct-current voltage; and an inverter arranged to perform a switching operation at a switching frequency, to convert an output voltage of the converter into an alternating-current voltage, and to output the alternating-current voltage to a discharge tube; wherein the inverter includes a switching circuit arranged to perform the switching operation with a substantially constant on-duty ratio and a burst control circuit arranged to perform burst control in which active and inactive states are repeated at a frequency that is less than the switching frequency and to control a ratio between an active period and an inactive period of the burst based on an externally input control signal; and the converter is arranged to operate regardless of the active or inactive state of the burst control in the inverter and includes a negative feedback control circuit arranged to stabilize a voltage or a current of the discharge tube in response to a detection signal of the voltage or the current of the discharge tube; the discharge tube lighting apparatus further comprising: a load detecting circuit arranged to detect the voltage or the current of the discharge tube in the active period of the burst control in the inverter and to supply the detection signal to the converter.