Patent ID: 8247987

Claim:
An induction lamp lighting device, comprising: an induction coil arranged adjacent to an induction lamp; a direct current power supply circuit for outputting a direct current voltage; a high-frequency power supply circuit for converting the direct current voltage to an alternating current voltage and supplying the alternating current voltage to the induction coil; and a control circuit for controlling the direct current power supply circuit and the high-frequency power supply circuit, wherein the control circuit is configured to perform a startup preparation operation by which to control the high-frequency power supply circuit so that, immediately after the alternating current voltage begins to be outputted from the high-frequency power supply circuit to the induction coil, the alternating current voltage is gradually increased to such a voltage value as not to generate arc discharge in the induction lamp and then kept at the voltage value for a specified time, wherein the control circuit is configured to perform a startup operation by which to control the high-frequency power supply circuit so that, after termination of the startup preparation operation, the alternating current voltage is gradually increased to a specified voltage value and then kept at the specified voltage value until the induction lamp is lighted up, and wherein the induction lamp lighting device further comprises a voltage detection circuit for outputting a detection voltage whose value grows higher as the amplitude of the alternating current voltage becomes greater, and wherein, during the startup preparation operation and based on the detection voltage, the control circuit is configured to perform a feedback control operation by which the alternating current voltage is kept constant.