PURPOSE:To achieve low electric power consumption for quartz oscillating circuit, by the control of a lower voltage than the battery voltage with the control circuit, after the specified time with the battery voltage fed to the oscillating circuit, in the quartz oscillating circuit using complementary MOS inverter. CONSTITUTION:The power supply line switching circuit 38 turns on at the leading of oscillation and the battery voltage VD is fed to the quartz oscillating circuit 31. The oscillation frequency is frequency-divided at the frequency division circuit 32. The output drives the display set for watches and it is fed to the control signal generation circuit via the gate circuit 33, and after the count of a given number, i.e. after a given time elapsed, the output is inverted to turn off the gate 33, thereby causing the switching circuit 38 off to operate the voltage control circuit 37 and allowing to supply a low voltage to the oscillating circuit 31. The battery voltage detection circuit 35 produces an output when the battery voltage is lower than a given voltage, or at a low temperature, if voltage drop is taken place, allowing to turn on the switching circuit 38 via the OR circuit 36 and to supply the battery voltage VD to the oscillating circuit 31.
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