| 摘要 |
PURPOSE:To prevent wasteful consumption of power and suppress generation of excessive voltage by furnishing a control circuit to restrict oscillation output from an inverter circuit when the total filemants of discharge lamps in series connection are not fitted perfectly. CONSTITUTION:When a filament f2 or f3 commonly connected with discharge lamps l1, l2 in series connection is out of connection, the sensing power of a filament sensing circuit 3 goes out, and when a filament f1 or f4 is out of connection, the sensing output of a voltage sensing circuit 2 connected between the other end of a capacitor C1 and the other end of a DC power supply E will go out. An output control circuit 4 restricts the oscillation output of an inverter circuit 1 when either of the sensing outputs of the mentioned circuits 2, 3 has gone out, and thereby wasteful consumption of the electric power and generation of excessive voltage are prevented. |
