Thereafter, When the set pulse is detected from the oscillator 2, the Q-output of the latch circuit 5 is restored to H. When the Q-output of the latch circuit 5 becomes H, the
driver D1 holds the sWitch S1 ON, While the driver D2 holds the sWitch S2 OFF. The subsequent operations are the same as those performed at the times T0 through T2.