A PFM control circuit generates a pulse control signal for controlling a
switching regulator to convert an input voltage into an output voltage.
The pulse control signal has a plurality of switch cycles, each of which
consists of an ON-time and an OFF-time. The ON-time is applied to turn on
a switching circuit of the switching regulator while the OFF-time is
applied to turn off the switching circuit. A current detection signal is
representative of a current flowing through an inductive device of the
switching regulator. The ON-time is prolonged in accordance with an
increase of a maximum of the current detection signal. A voltage
detection signal is representative of the output voltage. The OFF-time is
prolonged in accordance with a reduction of a falling rate of the voltage
detection signal.