OSCILLATION CIRCUIT

PURPOSE:To stabilize the oscillation circuit over wide-range power supply voltages and to reduce current consumption by using the MOS transistor of a low threshold voltage as a current source and controlling the through current of the circuit to amplify and output an oscillated output according to the current. CONSTITUTION:The current amount of I2. is controlled by the dimension ratio of P channel enhancement MOS transistors TR 2 and 5. The value of this current I2, is set by P and N channel enhancement MOS TR 6 and 7 as positive circuit elements for amplifying vibrations outputted from a crystal oscillator 24 so as to obtain the oscillated output of a desired frequency. Since current mirror connection with all the TR 4 is performed to N channel enhancement MOS TR 8, the current amount of the current I2. is controlled by the dimension ratio of the TR 4 and 8. When the power supply voltage is gradually increased and the static characteristic of N channel depression MOS TR 1 and 2 is considered, concerning a potential VA of a node A, the value of a voltage (VDD, VA) is not increased in comparison with the increase of the power supply voltage but turns to an almost fixed voltage value.