| 摘要 |
PURPOSE:To increase the degree of freedom in design relating to packaging patterns of a circuit substrate without limiting the pattern width of a grounding line by forming a wiring for a temp. fuse so as to commonly use this wiring as the grounding line. CONSTITUTION:A supply voltage Vcc of a DC is impressed to the other end of a capacitor C 1 grounded at one end and is impressed directly to one end of a coil L1 and the other end of a capacitor C 2 grounded at one end. On the other hand, both emitters of transistors Tr 1 and Tr 2 are grounded via the temp. fuse 21. This temp. fuse 21 is disposed in the state of maintaining tight contact with a fluorescent tube and shuts off the fluorescent tube to stop the DC/AC conversion operation by the Tr 1 and Tr 2 when the fluorescent tube generates heat at an abnormally high temp. The temp. fuse has an effect of preventing fuming and igniting of the circuit. In this case, the terminals of the fluorescent tube and the terminal for the temp. fuse 21 are commonly connected to the grounding line to make the pattern of the grounding line possible to be formed to be sufficiently wide. |
