An LCD backlight inverter has a buck switch for determining power supply to
a DC/AC converter for converting voltage, the buck switch being connected
between a supply voltage input terminal and the DC/AC converter. An
overvoltage protection circuit is connected to an input terminal of said
DC/AC converter for dividing voltage while providing a current path at the
time of the initial drive. A first comparing block compares the dimension
of a feedback signal with the dimension of a first reference voltage, the
feedback signal representing the voltage according to an on/off status of
the backlight. A second comparing block compares the dimension of the
voltage divided in the overvoltage protection circuit with the dimension
of a second reference voltage. A switching controlling block receives
comparison signals from the first and second comparing blocks for
controlling an on/off status of the buck switch according to the
comparison signals.