PURPOSE:To enable a titled circuit to be operated at a low volage supply, by taking a reference voltage of a comparator as an output power supply and forming independently a constant current source of a comparator and a charging source from other power supplies. CONSTITUTION:When a potential of a time constant circuit 5 is larger than a reference potential (b), a transistor(TR)Q2 turns on to decrease the reference potential (b) and a TRQ5 is turned off to stop charging and to start discharging. When a potential (a) is smaller thanthe reference potential (b), the TRQ2 turns off to restore the reference potential (b) and to restart charging. As a result, an oscillating signal having an amplitude determined with a reference power supply VS and resistor groups R1-R3 is outputted to an output terminal 1. Further, since there is a volage drop portion due to a TRQ4 only in the charging power supply 4, a voltage amplitude of a power supply VCC is utilized effectively. Thus, the amplitude output determined with the reference power supply VS and a resistor group 6 is obtained at a low voltage supply.
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