| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage controlled oscillator provided with input/output characteristics independent of the variation of an operation temperature and a process and capable of obtaining a high oscillation frequency. SOLUTION: A ring oscillator part 20 is constituted of inverter units U1, U2...Un. A current flowing to respective inverters is controlled by the current flowing to the P channel transistor P1 of a V-I conversion part 10 and the P channel transistor P3 for constituting a current mirror circuit. In this case, for a voltage VDP3 between the drain and source of the P channel transistor P3, the drain voltage of the P channel transistor P4 is supplied so as to perform operation at the boundary of a saturation area and a non-saturation area.
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