| 摘要 |
PROBLEM TO BE SOLVED: To provide a PLL circuit provided with a VCO whose output frequency characteristic is nearly linear within a variable range of an input voltage VCOIN. SOLUTION: A voltage current conversion circuit 21 operated at a high second power supply voltage Vdd2 higher than a first power supply voltage Vdd1 converts an input voltage VCOIN into current and outputs the current to a third current mirror circuit 24 and each gate of PMOS transistors P1 to Pm operated by a first power supply voltage Vdd1 whose voltage is lower than that of the second power supply voltage Vdd2, via first and second current mirror circuits 22, 23 operated by the second power supply voltage Vdd2, and the third current mirror circuit 24 outputs the current to an NMOS transistor 25 and each gate of NMOS transistors N1 to Nm.
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