INTEGRATED CIRCUIT

PURPOSE:To reduce total operating current consumption and to increase the lifetime of a battery by operating a circuit system with a low voltage with small current consumption at the time of low speed operation. CONSTITUTION:When an electric calculator function is operated, high speed oscillation means 6 of 455kHz is operated, and a load circuit 7 is operated with a high speed clock. In this case, a high voltage is supplied from a high voltage source 9 for generating a voltage for operating the circuit 7 with the high speed clock to the circuit 7 through selecting means 10. In this instance, since a clocking function is operated, low speed oscillation means 5 of 32.768Hz is operated, and the maximum oscillation frequency of this case becomes 455kHz. If only the clock function is operated and the calculator function is not operated, only the means 5 is operated, a low output voltage 81 of a low voltage source 8 for generating a lowest limit voltage is switched to be supplied to the operating voltage 101 of the circuit 7 through the means 10.