A discharge-lamp lighting circuit designed to decrease the size of a
driving circuit for driving switching elements constituting a DC-AC
converter circuit 4 therein and to reduce the manufacturing cost likewise.
With a bridge type circuit arrangement having a plurality of switching
elements SW1 to SW4 in the DC-AC converter circuit 4, a plurality of
bipolar transistors are used to form a driving circuit for controlling the
on-off conditions of the elements SW1 and SW3 positioned on the high
voltage side out of the switching elements. At this time, a plurality of
transistors (22 and 23) are connected in series and the on-off conditions
of the switching element SW1 are controlled by the transistor 23 on the
low voltage side. Moreover, there is provided a resistance element 26 so
as to limit current flowing from the node .alpha. between the switching
elements forming the arms of the bridge to the transistor. Switching speed
of the proper transistor 23 is also improved by controlling the base
current flowing into the transistor.
