| 摘要 |
<P>PROBLEM TO BE SOLVED: To avoid a needless protection operation during a start-up period after the lighting of a lamp is started. <P>SOLUTION: A low pressure discharge lighting device has a power supply circuit for supplying AC power to a low pressure discharge lamp, a voltage detecting circuit for detecting the lamp voltage of the low pressure discharge lamp, and a control circuit for controlling the power supply circuit on the basis of the detected lamp voltage of the voltage detecting device. The control circuit is configured to execute an operation of protecting the power supply circuit when the detected lamp voltage is equal to or less than a predetermined threshold value. A first threshold value is applied as the predetermined threshold value within a predetermined time period after the start of the lighting of the discharge lamp, and a second threshold value is applied after the predetermined time period elapses. The first threshold value is set to be lower than the second threshold value. <P>COPYRIGHT: (C)2012,JPO&INPIT |
