A multiplicity of synchronized inverters for driving a multiplicity of
loads such as CCFLs that require high ac voltages are arranged in close
proximity of the respective loads and controlled in phase. A frequency
determination capacitor and a frequency determination resistor are
connected to one of the inverters to generate a triangular wave signal
and a clock signal. The triangular wave signal and clock signal thus
generated are supplied to other inverters to synchronize all the loads so
that they can be controlled in phase. The resistance of the frequency
determination resistor is set to a substantially small magnitude at the
time of startup to increase the frequency of the triangular wave signal,
thereby enabling quick startup of the loads.