an oscillator Which generates a signal of a predetermined cycle;
a first comparing signal generating circuit Which generates a first comparing signal that synchroniZes With the signal of the predetermined cycle
a latch circuit Which selectively holds either a set state or a reset state;
a driving circuit Which drives the sWitch based on a state held by the latch circuit;
a capacitor Which stores an electric charge Which is used When said driving circuit holds the sWitch ON;