A control circuit has a delay correction circuit for correcting a delay
involved for driving a switching element. The delay correction circuit
has a reference voltage generating circuit for generating a reference
voltage, a first comparator for comparing the reference voltage with a
driving control signal to produce a first comparison result signal, an
error signal generating circuit for generating a lag direction signal or
a lead direction signal on the basis of the first comparison result
signal and a zero-current detected signal, a voltage level error signal
generating circuit for generating a voltage level error signal in
response to the lag direction signal or the lead direction signal, a
timer for producing a timer signal having a predetermined sawtooth
waveform, and a second comparator for comparing the voltage level error
signal with the timer signal to produce a second comparison result signal
as a delay correction signal.