| 摘要 |
PROBLEM TO BE SOLVED: To prevent damages to switching elements of a high-frequency inverter that supplies high-frequency power to the load circuit of a discharge lamp including a series resonance circuit, in response to a DC power supply by preventing a through-current from flowing in the switching elements. SOLUTION: A discharge lamp lighting device comprises a half-bridge type inverter which converts a DC power supply V received into a high-frequency and connected to a series resonance circuit including a discharge lamp 4, a control circuit 7 for controlling the inverter, and a voltage detection circuit 13 for detecting the voltage of the dc power supply V and applying controlling power to the control circuit 7, when the voltage detected is equal to or greater than a predetermined voltage. Switching elements 1, 2 are repeatedly turned on and off by control signals from the control circuit 7, at the application of the controlling power to operate the inverter to light the discharge lamp 4. Thereby the currents of the switching elements are delayed more than the voltages, and a current phase is established, with no through-current flowing or the switching elements 1, 2 afflicted with damages, whereby the rating of the switching elements can be optimized. |
