Widening the frequency range without increasing the power consumption. Current circuits output charge current based on control current. Capacitors are provided in association with the current circuits and store the charge current. Discharge transistors are provided in association with the capacitors and cause the capacitors to discharge electric charge. On-off transistors are connected between the current circuits and the capacitors and open or close the paths between the current circuits and the capacitors in accordance with the voltages across the capacitors. Signal output transistors have their gates connected between the current circuits and the on-off transistors and output signals to a flip-flop in accordance with the charge current. The flip-flop drives the discharge transistors alternately in accordance with the signals.