| 摘要 |
PURPOSE: An oscillator circuit is provided to prevent an abnormal oscillating phenomenon and use an external crystal oscillator of a wide frequency band by changing a gain of an amplifier to a suitable value according to a clock frequency of the external crystal oscillator. CONSTITUTION: An oscillator comprises a changeable resistant unit(20,30) controls a gain of an amplifier(10) and a control unit(40) more over to an existing oscillator circuit. The control unit(40) generates a control signal in order to control a resistance value of the changeable resistant units(20,30) according to a clock frequency outputted from the amplifier(10). The changeable resistant unit(20,30) is made up of a pull-up resistant unit(20) and a pull-down resistant unit(30). The pull-up resistant unit(20) is comprised of an N number of switching load device parallel coupled to the inputted end of a power source voltage(VDD) of a CMOS(complementary metal oxide semiconductor) invertor(10). The pull-down resistant unit(30) is comprised of an N number of switching load device parallel coupled to the inputted end of a basis voltage(VSS) of a CMOS invertor(10).
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