To provide an oscillation circuit which operates even with low power voltage of 1V or below, with which a constant frequency is obtained with respect to fluctuation of power voltage and which has less fluctuation of the frequency.

The circuit is provided with a constant voltage circuit 1 generating reference voltage Vref, a capacitor Co charging/discharging current, a charge/discharge circuit 5 controlling charging/discharging of the capacitor Co, a comparator 2 detecting charge/discharge voltage of the capacitor Co, a comparator 3 detecting charge/discharge voltage of the capacitor Co, and a logic circuit 4 forming a control signal for controlling charge/discharge timing of the capacitor Co. Thus, an oscillation operation becomes possible even if power voltage is about 0.8V by shifting actual operation voltage of triangular wave output Vtri by (resistance value)×(constant current value), by setting operation points of the two comparators 2 and 3 to Vref as an intermediate value of comparator power voltage and using a differential circuit which does not use a constant current source (tail current source) for the comparators 2 and 3.

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