| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device simplified in circuit configuration and enabling detection of installation and voltage. SOLUTION: If the filaments FL1, FL2 of a fluorescent lamp FL are removed, a dc component ceases to flow in a voltage detector circuit 23, and so a capacitor C17 is not charged, a gate voltage to a field effect transistor Q12 is reduced or stopped, and an inverter circuit 22 reduces or stops its output. When the fluorescent lamp FL is installed, a closed path to the voltage detector circuit 23 is formed by the filaments FL1, FL2, so a gate voltage is applied to the gate of the field effect transistor Q12 and the inverter circuit 22 starts to operate. Even if the input voltage of the inverter circuit 22 is low, the output of the inverter circuit 22 is reduced or stopped because the field effect transistor of the voltage detector circuit 23 is not charged by a predetermined amount. |
