| 摘要 |
PROBLEM TO BE SOLVED: To achieve small size and low cost in the drive circuit of switching elements that constitute a DC-AC conversion circuit in the discharge lamp lighting circuit. SOLUTION: In the case that the DC-AC conversion circuit 4 has a circuit structure of a bridge type made of a plurality of switching elements SW1-SW4, a drive circuit is constructed by using a plurality of bipolar transistors in order to control ON/OFF state of the elements SW1, SW3 that are positioned on the higher stage side of the switching elements. In this case, a plurality of transistors (22, 23) are connected in series and the ON/OFF state of the switching element SW1 is defined by the transistor 23 on the lower stage side. A resistance element 26 is provided so as to limit the current flowing in the transistor from the connecting pointαof the switching elements constituting the arm of the bridge, and the switching speed of the transistor is improved by controlling the base current flowing in the transistor 23. COPYRIGHT: (C)2003,JPO |
