| 摘要 |
PURPOSE:To simplify construction and to prevent welding of contact points, degradation and damage of components by commonly using one inverter circuit for both electrification and interruption of commercial power supply and making one inverter circuit to be always in its state of connection to a lamp. CONSTITUTION:There are provided an inverter circuit 2, driven by a DC power supply, for lighting a lamp L by means of a high frequency output, a voltage reducing circuit 3 for outputting a DC voltage lower than that of a commercial power supply AC, and a voltage booster circuit 4 for outputting a DC which is boosted from an output voltage of a battery B to a set voltage near the output voltage of the voltage reducing circuit 3. There is also provided a power supply switching circuit 5 by which, when the commercial power supply AC is electrified, operation of the voltage booster circuit 4 is made to stop, so that the output of the voltage reducing circuit 3 may work as the power supply of the inverter circuit 2, and when the power supply is interrupted, the voltage booster circuit 4 is operated, so that the output of the voltage booster circuit 4 works as the power supply of the inverter circuit 2. Therefore, one inverter circuit 2 is commonly used for both electrification and interruption of the commercial power supply and, the inverter circuit 2 is always in its state of connection to the lamp L. Thus, degradation and damage of components are prevented, and simplification and miniaturization of construction can be realized. |
